Bit stream separating and merging system, apparatus, method and computer program product

ABSTRACT

Herein disclosed is a multiple-output bit stream separating apparatus for inputting an original MPEG-2 bit stream to separate into a plurality of transcoded MPEG-2 bit streams and a plurality of differential bit streams, and a multiple-output bit stream merging apparatus for inputting the transcoded MPEG-2 bit stream and the differential bit streams to reconstruct the original MPEG-2 bit stream. The bit rate of the transcoded MPEG-2 bit stream and the differential bit streams thus multiple times separated are much lower than that of the original MPEG-2 bit stream. This leads to the fact that the multiple-output bit stream separating apparatus and the multiple-input bit stream merging apparatus can promptly and reliably transmit and receive an original MPEG-2 bit stream having a large bit rate by transmitting and receiving a plurality of transcoded MPEG-2 bit streams and a plurality of differential bit streams in place of the original MPEG-2 bit stream.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to apparatuses, methods and computerprogram products for separating and merging a coded moving picturesequence signal, and more particularly, to apparatuses, methods andcomputer program products for transcoding a first coded moving picturesequence signal to separate into and generate a second coded movingpicture sequence signal and a differential coded moving picture sequencesignal, which is a difference between the first coded moving picturesequence signal and the second coded moving picture sequence signal, andmerging the second coded moving picture sequence signal and thedifferential coded moving picture sequence signal to reconstruct thefirst coded moving picture sequence signal.

2. Description of the Related Art

There have so far been proposed a wide variety of systems forcompressing and encoding a moving picture having a considerable amountof data to produce a coded moving picture sequence signal. Theinternational standard, ISO-IEC 13818, was created for a system operableto encode a digital video signal with an associated digital audio signaland commonly called “Moving Picture Expert Group Phase 2”, i.e.,“MPEG-2”. In such an encoding system, the coded moving picture sequencesignal is outputted in the form of bit streams. In particular, the bitstreams conformable to the above MPEG-2 standard will be referred to as“MPEG-2 bit streams” hereinlater. Recently, the system of this typebecomes more utilizable for various technical fields, such as acommunications system, a television broadcasting service system, and soon.

The above MPEG-2 bit stream have a hierarchical structure consisting of:in turn, a top, sequence layer; a GROUP OF PICTURES layer; a picturelayer; a slice layer, a macroblock layer; and a low, block layer.

The typical encoder operates under the MPEG-2 standard through a methodof compressing and encoding a moving picture as follows. The methodcomprises the steps of:

-   (a) inputting the moving picture sequence consisting of a series of    pictures;-   (b) temporarily storing the series of pictures as frames in    memories, respectively;-   (c) computing a difference between one frame and another frame to    eliminate redundancy in a time axis direction; and-   (d) orthogonal transforming, e.g., discrete cosine transforming    (DCT), a plurality of picture elements within each of the frames to    eliminate redundancy in a spatial axis direction.

The encoder thus constructed can compress and encode the moving pictureto generate and output a coded moving picture sequence signal in theform of the MPEG-2 bit stream through a transmitting path at apredetermined bit rate. The coded moving picture sequence signal is thentransmitted from the encoder to a decoder which is operated to decodethe coded signal to reproduce the moving picture. The typical decoder isoperated to decode the coded moving picture sequence signal through aso-called bi-directionally predicting method which comprises the stepsof:

-   (a) storing one reproduced picture, generally referred to as    “intra-picture”, i.e., “I-picture”, in a first frame memory;-   (b) estimating another picture generally referred to as    “predictive-picture”, i.e., “P-picture”, followed by the I-picture,    on the basis of the information on the difference between the    I-picture and P-picture;-   (c) storing the estimated. P-picture in a second frame memory; and-   (d) estimating further another picture interposed between the    I-picture and P-picture, generally referred to as “bi-directionally    predictive-picture”, i.e., “B-picture”.

Here, the I-picture is encoded independently of the pictures of theother types, so that an I-picture can be reproduced as a single staticimage only by itself. A P-picture can be predicted on the basis of theI-picture or another P-picture located on a position prior to theP-picture to be encoded. I-picture is referred to as “intra-picture”while P-picture and B-picture are referred to as “inter-pictures”.

In the above encoder, the amount of information on the coded movingpicture sequence signal is, however, variable. In particular, the amountof information increases remarkably when a scene is changed. The decoderis generally provided with an input buffer for receiving the codedmoving picture sequence signal from the encoder. The input buffer of thedecoder, however, has a limited storage capacity. Therefore, when alarge number of bits of the coded moving picture sequence signal aretransmitted from the encoder to the decoder, the input buffer overflowswith the bits of the coded moving picture sequence signal thereby makingthe decoder difficult to process the coded moving picture sequencesignal. In order to transmit such coded moving picture sequence signalhaving a variable number of bits through the transmitting path at apredetermined bit rate and to make it possible for any decoder toreceive the whole of the coded moving picture sequence signal withoutoverflow, the encoder comprises: an output buffer for temporarilystoring the coded moving picture sequence signal before transmitting thecoded moving picture sequence signal through the transmitting path; anda rate controller for controlling the amount of bits of the coded movingpicture sequence signal stored in the output buffer so as to keep theamount of bits of the coded moving picture sequence signal to betransmitted to the decoder for a predetermined time from exceeding thecapacity of the input buffer of the decoder, thereby controlling the bitrate of the coded moving picture sequence signal.

A typical rate controlling method in MPEG-2 standard is described in“ISO-IEC/JTC1/SC29/WG11/N0400 Test Model 5”, April, 1993, hereinlaterreferred to as “TM-5”. The rate controlling method according to the TM-5comprises the steps of:

-   (I) allocating a target number of bits to a picture of each type on    the basis of the total number of bits, i.e., R, available to the    pictures to be encoded in the GROUP OF PICTURES;-   (II) computing the reference value of a quantization parameter used    for the quantization of each of macroblocks in the picture on the    basis of the utilization capacity of a “virtual buffer” to perform    the rate control; and-   (III) modulating the reference value of the quantization parameter    in accordance with the spatial activity in the macroblock.

Furthermore, there are many types of decoders. For instance, a decoderis designed to decode the coded signal in a unique compression formatdifferent from that of the MPEG-2 bit stream, and another decoder isconnectable to a transmitting path having a different bit rate. Thedecoder of those types is therefore required to provide with anapparatus, a so-called transcoder, for converting the MPEG-2 bit streamsinto another appropriate coded signal in a specified format having arequired bit rate. The transcoder makes it possible for the encoder totransmit the coded signal to any types of decoders.

Referring to FIG. 14 of the drawings, there is shown a transcoder of onetypical type as a first conventional transcoder 50. The conventionaltranscoder 50 has an input terminal a₁ electrically connected to a firsttransmitting path, not shown, and an output terminal a₂ electricallyconnected to a second transmitting path, not shown. The conventionaltranscoder 50 is designed to input first bit streams b₁ at apredetermined input bit rate through the input terminal a₁, to convertthe first bit streams b₁ into second bit streams b₂ to be outputted at apredetermined output bit rate, i.e., a target bit rate, lower than theinput bit rate of the inputted first bit streams b₁, and then to outputthe second bit streams b₂ through the output terminal a₂. Theconventional transcoder 50 comprises a variable length decoder 51,referred to as “VLD” in the drawings, an inverse quantizer 53, referredto as “IQ” in the drawings, a quantizer 55, referred to as “Q” in thedrawings, a variable length encoder 57, referred to as “VLC” in thedrawings, and a rate controller 59.

The variable length decoder 51 is electrically connected to the inputterminal a₁ and designed to decode a coded moving picture sequencesignal within the first bit streams b₁ inputted through the inputterminal a₁ to reconstruct original picture data for each of picturesincluding a matrix of original quantization coefficients, referred to as“level”, for each of macroblocks within each of the pictures and anoriginal quantization parameter, hereinlater referred to as “firstquantization parameter Q₁”.

The inverse quantizer 53 is electrically connected to the variablelength decoder 51 and designed to input the matrix of originalquantization coefficients level from the variable length decoder 51 andthe first quantization parameter Q₁. The inverse quantizer 53 is furtherdesigned to inversely quantize the inputted matrix of originalquantization coefficients level with the first quantization parameter Q₁to generate a matrix of inverse-quantization coefficients, referred toas “dequant”, i.e., DCT coefficients, for each of macroblocks asfollows: or $\begin{matrix}{{dequant} = {\left\{ {{2 \times {level}} + {{sign}({level})}} \right\} \times \frac{Q_{1} \times {QM}}{32}}} & {{equation}\quad({a1})} \\{{dequant} = {{level} \times \frac{Q_{1} \times {QM}}{16}}} & {{equation}\quad({a2})}\end{matrix}$

-   -   where the equation (a1) is used for the intra-picture while the        equation (a2) is used for the inter-picture. QM is a matrix of        quantization parameters stored in a predetermined quantization        table. The first quantization parameter Q₁ and the matrix of        quantization parameters QM are derived from the inputted first        bit streams b₁ by the decoder 51. Here, the original        quantization coefficients level, the inverse-quantization        coefficients dequant, the matrix of quantization parameters QM,        and the first quantization parameter Q₁ are integers. The        inverse-quantization coefficients dequant calculated by the        equations (a1) and (a2) should be rounded down to the nearest        integer.

The quantizer 55 is electrically connected to the inverse quantizer 53and designed to input the matrix of inverse-quantization coefficientsdequant from the inverse quantizer 53 and then quantize the inputtedmatrix of inverse-quantization coefficients dequant for each ofmacroblocks with a second quantization parameter, referred to as “Q₂”hereinlater, to generate a matrix of re-quantization coefficients,referred to as “tlevel”, as follows: $\begin{matrix}{{tlevel} = {{dequant} \times \frac{16}{Q_{2} \times {QM}}}} & {{equation}\quad({a3})} \\{{tlevel} = {{{dequant} \times \frac{16}{Q_{2} \times {QM}}} + {{sign}\quad({dequant}) \times \frac{1}{2}}}} & {{equation}\quad({a4})}\end{matrix}$or

-   -   where the equation (a3) is used for the inter-picture, while the        equation (a4) is used for the intra-picture. The second        quantization parameter Q₂ is obtained by the rate controller 59.        Here, the re-quantization coefficients tlevel and the second        quantization parameter Q₂ are also integers. The re-quantization        coefficients tlevel calculated by the equations (a3) and (a4)        should be rounded down to the nearest integer. Such rounding        operation for the integers will be omitted from the later        description for avoiding tedious repetition.

The variable length encoder 57 is electrically connected to thequantizer 55 and designed to input the re-quantization coefficientstlevel from the quantizer 55 and then encode the inputted matrix of there-quantization coefficients tlevel to generate objective picture datafor each of pictures to sequentially output the objective picture datain the form of the second bit streams b₂ through the output terminal a₂.The variable length encoder 57 is further electrically connected to thevariable length decoder 51 and designed to input a diversity ofinformation data included in the first bit streams b₁ necessary for thesecond bit streams b₂ from the variable length decoder 51.

The rate controller 59 is electrically connected to the inversequantizer 53 and designed to perform rate control process in accordancewith the TM-5 on the basis of the information obtained from the inversequantizer 53 as described below.

Referring to FIG. 15 of the drawings, there is shown a flowchart of therate controlling process in accordance with the TM-5 carried out in theconventional transcoder 50. As shown in FIG. 15, the rate controllingprocess comprises steps A1 to A14.

In the step A1, “1” is assigned to a picture number variable nrepresenting the serial number of a picture within the first bit streamsb₁. Hereinlater, a n-th picture in the first bit streams b₁ is referredto as “pic(n)”.

In the following step A2, a global complexity measure, referred to asX_(i), X_(p), or X_(b), for a picture of the corresponding type, i.e.,I, P or B-picture is computed as follows:X _(i) =S _(i) ×Q _(i)  equation (a5)orX _(p) =S _(p) ×Q ^(p)  equation (a6)orX _(b) =S _(b) ×Q _(b)  equation (a7)

-   -   where S_(i), S_(p), or S_(b) is the number of bits generated for        an encoded I, P or B-picture, and Q_(i), Q_(p), or Q_(b) is the        average quantization parameter computed by averaging the actual        quantization values used during the quantization of the all        macroblocks within I, P or B-picture. The average quantization        parameters Q_(i), Q_(p), and Q_(b) are normalized within a range        of 1 to 31. The average quantization parameters Q_(i), Q_(p),        and Q_(b) respectively correspond to the first quantization        parameters Q₁ obtained from the variable length decoder 51.

The global complexity measure X_(i), X_(p), or X_(b) of thecorresponding picture is inversely proportional to the compressing ratioof the moving picture, namely, the ratio of the amount of information inthe second bit streams b₂ to that in the first bit streams b₁. Namely,as the amount of information in the first bit streams b₁ becomes larger,the compressing ratio is decreased. Therefore, the global complexitymeasure X_(i), X_(p), or X_(b) of the corresponding picture becomeslarger, as the compressing ratio is decreased. In contrast, the globalcomplexity measure X_(i), X_(p), or X_(b) of the corresponding picturebecomes smaller, as the compressing ratio is increased.

The initial value of global complexity measure X_(i), X_(p), or X_(b) ofthe corresponding picture is given as follows:X _(i)=160×Target_Bitrate/115  equation (a8)orX _(p)=60×Target_Bitrate/115  equation (a9)orX _(b)=42×Target_Bitrate/115  equation (a10)

-   -   where Target_Bitrate is measured in bits/s and corresponds to        the target bit rate of the first conventional transcoder 50.

In the following step A3, the target number of bits for a picture of thecorresponding type, i.e., I, P or B-picture to be encoded in the currentGROUP OF PICTURES, referred to as T_(i), T_(p), or T_(b) is computed as:$\begin{matrix}{T_{i} = {\frac{R}{1 + \frac{N_{p}X_{p}}{X_{i}K_{p}} + \frac{N_{b}X_{b}}{X_{i}K_{b}}}\quad{or}}} & {{equation}\quad\left( {a\quad 11} \right)} \\{T_{p} = {\frac{R}{N_{p} + \frac{N_{b}K_{p}X_{b}}{K_{b}X_{p}}}\quad{or}}} & {{equation}\quad({a12})} \\{{T_{b} = \frac{R}{N_{b} + \frac{N_{p}K_{b}X_{p}}{K_{p}X_{b}}}}\quad} & {{equation}\quad({a13})}\end{matrix}$

-   -   where N_(p) and N_(b) are the number of P-pictures and        B-pictures remained not yet encoded in the current GROUP OF        PICTURES, respectively. K_(p) and K_(b) are constants computed        on the basis of the ratio of the quantization value of P-picture        to the quantization value of I-picture, and the ratio of the        quantization parameter of B-picture to the quantization value of        I-picture, respectively. It is assumed that the quality of the        whole image will be always optimized with K_(p)=1.0 and        K_(b)=1.4.

In the following step A4, it is judged upon whether the picture numbervariable n is “1” or not, i.e., the current picture is the first picturepic(1) or not. When it is judged that the picture number variable n is.“1”, i.e., the current picture is the first picture pic(1), the step A4goes forward to the step A5. When, on the other hand, it is judged thatthe picture number variable n is not “1”, i.e., the current picture isnot the first picture, the step A4 goes forward to the step A6. In thestep A5, the total number of bits available to the pictures to beencoded in the current GROUP OF PICTURES, i.e., the remaining number ofbits available to the GROUP OF PICTURES, hereinlater referred to as R,is initialized in accordance with the following equation (a14). Thisremaining number of bits available to the GROUP OF PICTURES R beforeencoding the first picture pic(1) within the GROUP OF PICTURES iscomputed as follows:R=Target_Bitrate×NPIC/picture_rate+R  equation (a14)

-   -   where NPIC is the total number of pictures of any type in the        GROUP OF PICTURES, and picture_rate is expressed in the number        of pictures decoded and indicated per second. At the start of        the sequence R=0.

In the step A6, the above remaining number of bits available to theGROUP OF PICTURES R before encoding the current picture pic(n) isupdated as follows:R=R−S _(i)  equation (a15)orR=R−S _(p)  equation (a16)orR=R−S _(b)  equation(a17)where S_(i), S_(p), or S_(b) is the number of bits generated in thepreviously encoded picture pic(n−1) of the corresponding type (L P orB).

The step A5 or A6 goes forward to the step A7 wherein “1.” is assignedto a macroblock number variable j (j>=1) representing the serial numberof a macroblock within one of the pictures. Hereinlater, the j-thmacroblock in the picture is referred to as “MB(j)”.

In the following step A8, a utilization volume of the capacity of avirtual buffer for I, P or B-pictures, referred to as d_(i)), d_(p)(j)or d_(b)(i), before encoding the macroblock MB(j) is computed asfollows: $\begin{matrix}{{d_{i}(j)} = {{d_{i}(0)} + {B\left( {j - 1} \right)} - {\frac{T_{i} \times \left( {j - 1} \right)}{NMB}\quad{or}}}} & {{equation}\quad({a18})} \\{{d_{p}(j)} = {{d_{p}(0)} + {B\left( {j - 1} \right)} - {\frac{T_{p} \times \left( {j - 1} \right)}{NMB}\quad{or}}}} & {{equation}\quad({a19})} \\{{{d_{b}(j)} = {{d_{b}(0)} + {B\left( {j - 1} \right)} - \frac{T_{b} \times \left( {j - 1} \right)}{NMB}}}\quad} & {{equation}\quad({a20})}\end{matrix}$

-   -   where B(j−1) is the total number of bits generated for encoded        macroblocks in the picture up to and including the (j—1)th        macroblock MB(j—1). NMB is the total number of macroblocks in        the picture. d_(i)(j), d_(p)(j), or d_(b)(j) is the utilization        volume of the capacity of the virtual buffer at the j-th        macroblock MB(j) for I, P, or B-picture.

d_(i)(0), d_(p)(0), or d_(b(0)) is the initial utilization volume of thevirtual buffer for I, P, or B-picture and given by:d _(i)(0)=10×r/31.  equation (a21)ord _(p)(0)=K _(p) ×di(0)  equation (a22)ord _(b)(0)=K _(b) ×d _(i)(0)  equation (a23)where r is referred to as “reaction parameter” and used for the controlof the reaction rate of the feed back loop as follows:r=2×Target_Bitrate/picture_rate  equation (a24)

The final utilization volume of the virtual buffer, referred to as,d_(i)(NMB), d_(p)(NMB), or d_(b)(NMB) of the last macroblock, i.e.,NMB-th macroblock MB(NMB) of the current picture pic(n) will be used asthe initial utilization volume of the virtual buffer for I, P, orB-picture, i.e., d_(i)(0), d_(p)(0), or d_(b(0)) of the same type toencode the first macroblock MB(1) within the next picture pic(n+1).

In the following step A9, the reference quantization parameter Q(j) ofthe j-th macroblock MB(j) for each of the pictures is computed on thebasis of the aforesaid utilization volume of the virtual buffer, i.e.,d(j) as follows:Q(j)=d(j)×31/r  equation (a25)

Here, the reference quantization parameter Q(j) is identical with theaforesaid second quantization parameter Q₂ of the j-th macroblock MB(j).

In the following step A10, the j-th macroblock MB(j) is quantized withthe reference quantization parameter Q(j) computed in the step A9. Inthe following step A11, the macroblock number variable j is incrementedby one. The step A11 goes forward to the step A12 wherein it is judgedupon whether the macroblock number variable j is more than the totalnumber of macroblocks NMB within the n-th picture pic(n) or not. When itis judged that the macroblock number variable j is not more than thetotal number of macroblocks NMB within the n-th picture pic(n), the stepA12 returns to the step A8. When, on the other hand, it is judged thatthe macroblock number variable j is more than the total number ofmacroblocks NMB within the n-th picture pic(n), the step A12 goesforward to the step A13.

The macroblock number variable j thus serves as a loop counter forrepeating the process from the steps A8 to A11 to encode all themacroblocks from the 1st macroblock MB(1) up to the j-th macroblockMB(j) in the present picture pic(n). The entire macroblocks startingfrom the first macroblock MB(1) up to the NMB-th macroblock MB(NMB) inthe n-th picture pic(n) can be thus encoded sequentially.

In the step A13, the picture number variable n is incremented by one.Then the step A13 goes forward to the step A14 wherein it is judged uponwhether the picture number variable n is more than the total number ofpictures, i.e., NPIC or not. When it is judged that the picture numbervariable n is not more than the total number of pictures, NPIC, the stepA14 returns to the step A2. When, on the other hand, it is judged thatthe picture number variable n is more than the total number of pictures,NPIC, this routine of the rate controlling process is terminated. Thepicture number variable n thus serves as a loop counter for repeatingthe process from steps A2 to A13 to process all the pictures from thefirst picture pic(1) to the n-th picture pic(n) in the present GROUP OFPICTURES. The entire pictures starting from the first picture pic(1) upto the NPIC-th picture pic(NPIC), in the present GROUP OF PICTURES canbe therefore processed sequentially.

The aforesaid conventional transcoder 50, however, can obtain noinformation on the structure of GROUP OF PICTURES such as a picturecycle of I or P-pictures within each of the GROUP OF PICTURES, so thatthe transcoder 50 must estimate the structure of GROUP OF PICTURESwithin the inputted moving picture sequence signal to allocate thenumber of bits to pictures of each type within the estimated structureof GROUP OF PICTURES.

Furthermore, the first conventional transcoder 50 is required to decodethe first bit streams b₁ almost all over the layers such as the sequencelayer, the GROUP OF PICTURES layer, the picture layer, the slice layerand the macroblock layer in order to derive necessary data fortranscoding the first bit streams b₁ into the second bit streams b₂. Theoperation takes time, thereby causing the delay in the transcodingprocess.

Referring to FIG. 16 of the drawings, there is shown an improvement ofthe above transcoder 50 as a second conventional transcoder 60. Thesecond conventional transcoder 60 is operated to perform the ratecontrol without estimating the structure of GROUP OF PICTURES. As shownin FIG. 16, the second conventional transcoder 60 comprises a delaycircuit 61 and a rate controller 62 in addition to the variable lengthdecoder 51, the inverse quantizer 53, the quantizer 55 and the variablelength encoder 57 same as those of the first conventional transcoder 50shown in FIG. 14. The same constitutional elements are simplyrepresented by the same reference numerals as those of the conventionaltranscoder 50, and will be thus omitted from description for avoidingtedious repetition.

The delay circuit 61 is interposed between the variable length decoder51 and the inverse quantizer 53 and designed to control the flow of thesignal from the variable length decoder 51 to the inverse quantizer 53.The delay circuit 61 is operated to delay the operation start time ofthe inverse quantizer 53 so that the inverse quantizer 53 does not startthe inverse-quantizing process until the variable length decoder 51terminates the process of decoding one of the pictures in the codedmoving picture sequence signal.

As shown in FIG. 16, the rate controller 62 of the second conventionaltranscoder 60 includes a target ratio computing unit 63, an input bitsumming unit 65, a bit difference computing unit 67, a target output bitupdating unit 69, and a quantization parameter computing unit 71.

The target ratio computing unit 63 is electrically connected to thevariable length decoder 51 and designed to input an input bit rate ofthe first bit streams b₁, hereinlater referred to as “Input_Bitrate”,from the variable length decoder 51, and input a target bit rate,hereinlater referred to as “Target_Bitrate” through a terminal a₃.Alternatively, the target bit rate Target_Bitrate may have been storedin an internal memory, or determined on the basis of internal switches.The target ratio computing unit 63 is designed to then compute a targetratio, hereinlater referred to as “ioRatio” of the target bit rateTarget_Bitrate to the input bit rate Input_Bitrate for each of picturesas follows: $\begin{matrix}{{ioRatio} = \frac{Target\_ Bitrate}{Input\_ Bitrate}} & {{equation}\quad({a26})}\end{matrix}$

The input bit summing unit 65 is designed to sum up the number ofinputting bits of the picture decoded by the variable length decoder 51to produce the total number of inputting bits, hereinlater referred toas “T_(in)”. On the other hand, the target output bit updating unit 69is designed to compute a target number of outputting bits to begenerated by the variable length encoder 57, hereinlater referred to as“T_(out)”. The target number of outputting bits T_(out) is computed bymultiplying the total number of inputting bits T_(in) by the targetratio ioRatio as follows:T _(out) =T _(in) ×ioRatio  equation (a27)

The bit difference computing unit 67 is electrically connected to thevariable length encoder 57 and the target output bit updating unit 69,and designed to input a real number of outputting bits encoded by thevariable length encoder 57, hereinlater referred to as “T_(real)”, andinput the target number of outputting bits T_(out). The bit differencecomputing unit 67 is designed to then compute a difference between thetarget number of outputting bits T_(out) and the real number ofoutputting bits T_(real), hereinlater referred to as a “differencenumber of bits”, i.e., “T_(diff)” as follows:T _(diff) =T _(ral) −T _(out)  equation (a28)

The target output bit updating unit 69 is electrically connected to thetarget ratio computing unit 63, the input bit summing unit 65, and thebit difference computing unit 67. The target output bit updating unit 69is designed to update the target number of outputting bits T_(out) onthe basis of the difference number of bits T_(diff) as follows:T _(out) =T _(out) −T _(diff)  equation (a29)

The quantization parameter computing unit 71 is electrically connectedto the target output bit updating unit 69 and designed to compute thereference quantization parameter Q(j) for each of macroblocks MB(j) onthe basis of the target outputting bits T_(out) updated by the targetoutput bit updating unit 69 in accordance with the step II of the TM-5.

FIG. 17 shows the flowchart of the rate controlling process performed bythe above conventional transcoder 60. The rate controlling processperformed in the transcoder 60 comprises the steps B1 to B13. The stepsB6 to B13 are almost the same as those of the steps A7 to A14,respectively, in the rate controlling process shown in FIG. 15 exceptfor the step B7 wherein the utilization volume of the capacity of thevirtual buffer is computed on the basis of the target number ofoutputting bits T_(out) given by the target output bit updating unit 69instead of the target number of bits T_(i), T_(p) or T_(b) computed inthe step A3 shown in FIG. 15. The same steps will be thus omitted fromdescription for avoiding tedious repetition.

In the step B1, “1” is assigned to the picture number variable n. Thestep B1 then goes forward to the step B2 wherein the target ratioioRatio is computed by the above equation (a26). In the following stepB3, the difference number of bits T_(diff) is computed for the presentpicture pic(n) by the above equation (a28). The step B3 then goesforward to the step B4 wherein the number of inputting bits T_(diff) issummed up within the first bit streams b₁. In the step B5, the targetnumber of outputting bits T_(out) is computed by the above equation(a27), and further updated by the above equation (a29).

In the second conventional transcoder 60 thus constructed, the inversequantizer 53, however, cannot start the inverse-quantization processuntil the target transcoding frame is completely decoded, therebycausing the delay in the transcoding process.

Referring to FIGS. 18 and 19 of the drawings, there is shown anotherimprovement of the above transcoder 50 as a third conventionaltranscoder 80. The third conventional transcoder 80 is also adaptable toperform the rate control without estimating the structure of GROUP OFPICTURES. As shown in FIG. 18, the third conventional transcoder 80comprises an input terminal a₁ electrically connected to a firsttransmitting path and designed to input an input bit streams b₃ at theinput bit rate, and an output terminal a₂ electrically connected to asecond transmitting path and designed to output an output bit streams b₄at the target bit rate. In the third conventional transcoder 80, theinput bit streams b₃ may have a format, non-adaptable for the MPEG-2,different from that of the bit streams b₁ of the first and secondconventional transcoders 50 and 60. The input bit streams b₃ haveinformation on the number of coding bits previously recorded thereon bythe encoder, not shown.

The third conventional transcoder 80 comprises a variable length decoder81 electrically connected to the input terminal a₁, and a ratecontroller 82 in addition to the inverse quantizer 53, the quantizer 55,and the variable length encoder 57 which are same in construction asthose of the second transcoder 60 shown in FIG. 16. The rate controller82 includes a target output bit updating unit 83, and a quantizationparameter computing unit 85 in addition to the target ratio computingunit 63, and the bit difference computing unit 67 which are same asthose of the second transcoder 60 shown in FIG. 16.

The third conventional transcoder 80 thus constructed can perform therate control on the basis of the formation on the number of coding bitspreviously recorded in the input bit streams b₃. The variable lengthdecoder 81 is operated to decode the coded moving picture sequencesignal within the third bit streams b₃ to reconstruct the pictures andthe information on the number of coding bits, and transmit theinformation to the inverse quantizer 53. The variable length decoder 81is also operated to transmit the number of inputting bits T_(in) to thetarget output bit updating unit 83.

The outputting bit updating unit 83 is designed to compute the targetnumber of outputting bits T_(out) on the basis of the number ofinputting bits T_(in) and the target ratio ioRatio by the above equation(a26). The quantization parameter computing unit 85 is designed tocompute the reference quantization parameter Q(j) of the macroblocksMB(j) for each of pictures on the basis of the target number ofoutputting bits T_(out) updated by the outputting bit updating unit 83in accordance with the step II in the TM-5. The quantizer 55 is thenoperated to quantize the j-th macroblock MB(j) on the basis of thereference quantization parameter Q(j) given by the quantizationparameter computing unit 85.

FIG. 19 shows the flowchart of the rate controlling process performed bythe above third conventional transcoder 80. The rate controlling processperformed in the transcoder 80 comprises the steps C1 to C13. All thesteps C1 to C13 are the same as those of the steps B1 to B13,respectively, in the rate controlling process shown in FIG. 17 exceptfor the step C4 wherein the number of inputting bits T_(in) in thecurrent picture pic(n) is derived from the third bit streams b₃ by thedecoder 81 to compute the total number of inputting bits T_(in).

The third conventional transcoder 80 thus constructed has information onthe number of coding bits previously recorded in the third bit streamsb3 thereby making it possible to solve the problem of the delay in thesecond conventional transcoder 60. The third conventional transcoder 80,however, encounters another problem to restrict the form of the inputtedbit streams. Moreover, the encoder which is linked with the thirdtranscoder 80 must provide with the above information on the number ofcoding bits to be recorded in the bit streams, thereby causing the delayof process in the encoder.

In the conventional transcoders 50, 60 and 80, the matrix of theinverse-quantization coefficients dequant is necessary for only thequantizer 55, but unnecessary for the transcoder itself to generate thedesired bit streams. In order to eliminate the redundant matrix of theinverse-quantization coefficients dequant, there is proposed a fourthconventional transcoder 90 comprising a level converter 91 instead ofthe inverse quantizer 53 and the quantizer 55 of the transcoder 50, asshown in FIG. 20.

The level converter 91 is interposed between the variable length decoder51 and the variable length encoder 57. The level converter 91 isdesigned to input the original picture data for each of pictures. Theoriginal picture data includes a matrix of original quantizationcoefficients level for each of macroblocks within the correspondingpicture. The level converter 91 is electrically connected to the ratecontroller 59 and designed to input the second quantization parameter Q₂from the rate controller 59.

The level converter 91 is further designed to convert the originalpicture data for each of pictures including the matrix of originalquantization coefficients level into the objective picture dataincluding the matrix of re-quantization coefficients level withoutgenerating the matrix of the inverse-quantization coefficients dequant.The following equations (30a) and (31a) for the matrix ofre-quantization coefficients tlevel are lead by eliminating the matrixof the inverse-quantization coefficients dequant from the aboveequations (a1), (a2), (a3) and (a4). $\begin{matrix}{{tlevel} = \left\{ {\left( {{level} + {{{sign}({level})} \times \frac{1}{2}}} \right\} \times \frac{Q_{1}}{Q_{2}}} \right.} & {{equation}\quad\left( {30a} \right)} \\{{tlevel} = {{{level} \times \frac{Q_{1}}{Q_{2}}} + \frac{{sign}({level})}{2}}} & {{equation}\quad\left( {31a} \right)}\end{matrix}$

-   -   where the above equation (30a) is used for the inter-picture,        while the above equation (31 a) is used for the intra-picture.        The level converter 91 is thus operable to convert the original        picture data, for each of pictures, into the second picture data        with the first quantization parameter Q₁ and the second        quantization parameter Q₂. The first quantization parameter Q₁        is decoded from the first bit streams b₁ by the variable length        decoder 51, while the second quantization parameter Q₂ is        obtained from the rate controller 59.

In the fourth conventional transcoder 90, the rate controller 59 isdesigned to perform the rate control over the encoding process in thetranscoder 90 according to the TM-5. The variable length encoder 57 iselectrically connected to the level converter 91 and to input the abovematrix of re-quantization coefficients tlevel from the level converter91.

The fourth conventional transcoder 90 thus constructed can efficientlyperform the transcoding process at high speed without storing the matrixof inverse-quantization coefficients dequant in a memory.

The above conventional transcoders 50, 60, 80 and 90, however, encounteranother problem with the rate-distortion performance in converting thequantization level occurred as a result of the re-quantization operationsince they cannot obtain all the information on original picture databefore the quantization operation. In short, the rate-distortionperformance in converting the quantization level is unstable andvariable in accordance with the first and second quantization parametersand the level of the original quantization coefficients level.Therefore, as the amount of reduced information becomes larger, thequantization error is liable to increase, thereby causing unstable ratecontrol in transcoding.

The applicant of the present application filed a U.S. patent applicationSer. No. 09/604,973 on Jun. 28, 2000.

The applicant disclosed therein an apparatus, a method and a computerprogram product for transcoding a coded moving picture sequence signal,being operable to compute an optimized re-quantization parameter on thebasis of the inverse-quantization parameter and the previously computedre-quantization parameter in consideration of the characteristics of therate-distortion performance dependent on the re-quantization parameterand the inverse-quantization parameter.

The apparatus disclosed therein comprising an inverse quantizer forperforming the inverse-quantization operation and a quantizer forperforming the quantization operation, is characterized in that theapparatus further comprises quantization parameter switching means forswitching the quantization parameter in consideration of thecharacteristics of the rate-distortion performance dependent on theinputted quantization parameter, thereby making it possible for theapparatus to minimize the quantization error occurred when the matrix oforiginal quantization coefficients is transformed to the matrix ofre-quantization coefficients.

In the meantime, different techniques have been found such as datapartitioning and SNR scalability for dividing picture signals conveyingpicture information into two separate picture signals consisting of baselayer picture signal indicative of basic picture information andenhancement layer picture signal indicative of high quality pictureinformation in order to prevent the quality of picture fromdeteriorating.

More particularly, the data partitioning provides a method of dividingbit streams conveying picture information into two separate bit streamsconsisting of base layer bit streams conveying low-frequency DCTcoefficients and enhancement layer bit streams conveying high-frequencyDCT coefficients before encoding, and the base layer bit streams andenhancement layer bit streams thus divided are recombined beforedecoding. Original picture information can be roughly decoded andreproduced from the base layer bit streams conveying low-frequency DCTcoefficients, but not from the enhancement layer bit streams conveyinghigh-frequency DCT coefficients alone. The high-quality original pictureinformation can be decoded and reproduced from the recombination of thebase layer bit streams conveying low-frequency DCT coefficients and theenhancement layer bit streams conveying high-frequency DCT coefficients.

The SNR scalability provides a method of dividing picture signalscontaining picture information into two separate picture signalsconsisting of base layer picture signals containing low-SNR imageinformation and enhancement layer picture signals containing auxiliaryinformation before encoding. The method of SNR scalability will bedescribed in detail. The original picture signals have original DCTcoefficients. The quantizer is operated to roughly quantize base layerbit picture signals containing low-SNR image information to generatelow-SNR bit streams. The inverse quantizer is operated to inverselyquantize the low-SNR bit streams thus generated to roughly reproduce DCTcoefficients. Then, the difference information between the original DCTcoefficients and the reproduced DCT coefficients is extracted andquantized to generate the enhancement layer picture signals. Theenhancement layer picture signals thus generated are used as auxiliaryinformation in combination with the base layer picture signals (low-SNRsignals) to reproduce high-SNR signals.

The above described methods, however, encounter a problem of reducingthe quality of service, i.e., QoS. The transcoding process abovedescribed is non-reversible. The transcoder, in general, is operated todecode and inversely quantize DCT coefficients of input bit streams andre-quantize the DCT coefficients thus inversely quantized withre-quantization parameters greater then the original quantizationparameters to reduce the bit rate. This means that the input bit streamsbefore the transcoding operation cannot be reproduced from thetranscoded bit streams. This leads to the fact that the QoS for theinput bit streams cannot be reproduced.

The data partitioning method permits to divide bit streams into twoseparate bit streams consisting of base layer bit streams indicative oflow-frequency DCT coefficients and enhancement layer bit streamsindicative of high-frequency DCT coefficients before encoding. There is,however, provided no method of dividing MPEG-2 bit streams inconformance with MP@ML, which are not in a hierarchical structure, intobase layer bit streams and enhancement layer bit streams. Furthermore,although the data partitioning method may permit to divide bit streamsinto the base layer bit streams and enhancement layer bit streams beforeencoding, a decoder conforming to MP@ML cannot decode the base layer bitstreams and enhancement layer bit streams thus divided.

According to the syntax of the data partitioning, the code specifying aboundary between low-frequency coefficients and high-frequencycoefficients is defined as “Priority_break_point”, which makes itpossible for a decoder to distinguish the low-frequency coefficientsfrom the high-frequency coefficients. The decoder conforming to MP@ML,on the other hand, cannot recognize “Priority_break_point”. Furthermore,the bit streams indicative of low-frequency coefficients include no EOBcode, thereby making it impossible for the MP@ML decoder to reproducethe bit streams indicative of low-frequency coefficients. This leads tothe fact that the data partitioning method requires a decoder dedicatedto the data partitioning method in place of the decoder conforming toMP@ML.

Similarly to the data partitioning, the SNR scalability method permitsto divide bit streams into two separate bit streams consisting of baselayer bit streams containing low-SNR signals and enhancement layer bitstreams containing the auxiliary information before encoding. An encoderconforming to MP@ML, however, cannot divide bit streams into base layerbit streams containing low-SNR signals and enhancement layer bit streamscontaining the auxiliary information and encode the base layer bitstreams and enhancement layer bit streams thus divided. Nor can adecoder conforming to MP@ML decode the base layer bit streams and theenhancement layer bit streams. This leads to the fact that the SNRscalability method requires an encoder and a decoder dedicated to theSNR scalability in place of the encoder and decoder conforming to MP@ML.

Furthermore, the base layer bit streams and the enhancement layer bitstreams are required to be processed in parallel, thereby making itcomplex and difficult to design such SNR scalability conformable encoderand decoder. Moreover, the SNR scalability conformable decoder isoperated to receive the base layer bit streams and the enhancement layerbit streams to reproduce and output original picture signals but not inthe form of bit streams. This means that the picture signal thusreproduced and outputted must be transcoded again if it is required bein the form of bit streams.

That the above data partitioning and SNR scalability operations requirerespective dedicated encoders and decoders is attributed to the factthat the respective decoders and encoders are operative to perform theprocess of dividing bit streams into base layer bit streams and theenhancement layer bit streams, and the process of recombining the baselayer bit streams and the enhancement layer bit streams to reconstructoriginal bit streams.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide anapparatus for transcoding a first coded moving picture sequence signalto separate into and generate a second coded moving picture sequencesignal and a differential coded moving picture sequence signal, which isa difference between the first coded moving picture sequence signal andthe second coded moving picture sequence signal.

It is another object of the present invention to provide a method oftranscoding a first coded moving picture sequence signal to separateinto and generate a second coded moving picture sequence signal and adifferential coded moving picture sequence signal, which is a differencebetween the first coded moving picture sequence signal and the secondcoded moving picture sequence signal.

It is further object of the present invention to provide a computerprogram product for transcoding a first coded moving picture sequencesignal to separate into and generate a second coded moving picturesequence signal and a differential coded moving picture sequence signal,which is a difference between the first coded moving picture sequencesignal and the second coded moving picture sequence signal.

It is a still further object of the present invention to provide anapparatus for merging a second coded moving picture sequence signal anda differential coded moving picture sequence signal, which is adifference between the first coded moving picture sequence signal and asecond coded moving picture sequence signal, to reconstruct the firstcoded moving picture sequence signal.

It is a yet further object of the present invention to provide a methodof merging a second coded moving picture sequence signal and adifferential coded moving picture sequence signal, which is a differencebetween the first coded moving picture sequence signal and a secondcoded moving picture sequence signal, to reconstruct the first codedmoving picture sequence signal.

It is further object of the present invention to provide a computerprogram for merging a second coded moving picture sequence signal and adifferential coded moving picture sequence signal, which is a differencebetween the first coded moving picture sequence signal and a secondcoded moving picture sequence signal, to reconstruct the first codedmoving picture sequence signal.

In accordance with a first aspect of the invention, there is provided acoded signal separating and merging system comprising: a coded signalseparating apparatus for inputting a first coded moving picture sequencesignal to separate into a second coded moving picture sequence signaland a differential coded moving picture sequence signal; and a codedsignal merging apparatus for inputting the second coded moving picturesequence signal and the differential coded moving picture sequencesignal to reconstruct the first coded moving picture sequence signal.

The aforesaid coded signal separating apparatus includes: inputtingmeans for inputting the first coded moving picture sequence signaltherethrough, the first coded moving picture sequence signal generatedas a result of encoding original moving picture sequence signal andconsisting of a series of first picture information having firstcoefficient information, the first coefficient information including amatrix of first coefficients; coded signal converting means forconverting the first coded moving picture sequence signal inputtedthrough the inputting means to generate the second coded moving picturesequence signal, the second coded moving picture sequence signalconsisting of a series of second picture information having secondcoefficient information, the second coefficient information including amatrix of second coefficients, each of the first coded moving picturesequence signal, and the second coded moving picture sequence signal isin the form of a hierarchical structure including one or more sequencelayers each having a plurality of screens sharing common information,one or more picture layers each having a plurality of slices sharingcommon information with respect to one of the screens, one or more slicelayers each having a plurality of macroblocks with respect to one of theslices, one or more macroblock layers each having a plurality of blockswith respect to one of the macroblocks, and one or more block layerseach having block information with respect to one of the blocks;differential coded signal generating means for inputting the first codedmoving picture sequence signal and the second coded moving picturesequence signal from the coded signal converting means to generate adifferential coded moving picture sequence signal on the basis of thefirst coefficient information obtained from the series of first pictureinformation of the first coded moving picture sequence signal, and thesecond coefficient information obtained from the series of the secondpicture information of the second coded moving picture sequence signal,the differential coded moving picture sequence signal being a differencebetween the first coded moving picture sequence signal and the secondcoded moving picture sequence signal; separating storage means forselectively storing the first coded moving picture sequence signal, thesecond coded moving picture sequence signal, and the differential codedmoving picture sequence signal; and first transmission means forselectively transmitting the first coded moving picture sequence signal,the second coded moving picture sequence signal, and the differentialcoded moving picture sequence signal to the coded signal mergingapparatus.

The aforesaid coded signal merging apparatus includes first receivingmeans for receiving a base coded moving picture sequence signaltransmitted by the first transmission means from the coded signalseparating apparatus, the base coded moving picture sequence signalbeing any one of the first coded moving picture sequence signal, thesecond coded moving picture sequence signal, and the differential codedmoving picture sequence signal; merging storage means for storing thebase coded moving picture sequence signal received by the firstreceiving means; request signal determining means for determining arequest signal for a requested coded moving picture sequence signal onthe basis of the base coded moving picture sequence signal stored by themerging storage means; and request signal transmission means fortransmitting the request signal for the requested coded moving picturesequence signal determined by the request signal determining means tothe coded signal separating apparatus.

In the aforesaid coded signal separating apparatus may further include:request signal receiving means for receiving the request signaltransmitted by the request signal transmission means from the codedsignal merging apparatus; separating coded signal extracting means forextracting the requested coded moving picture sequence signal from theseparating storage means in response to the request signal; and secondtransmission means for transmitting the requested coded moving picturesequence signal extracted by the separating coded signal extractingmeans to the coded signal merging apparatus.

In the aforesaid coded signal merging apparatus may further include:second receiving means for receiving the requested coded moving picturesequence signal transmitted by the second transmission means from thecoded signal separating apparatus; merging coded signal extracting meansfor extracting the base coded moving picture sequence signal from themerging storage means; merging means for merging the base coded movingpicture sequence signal extracted by the merging coded signal extractingmeans with the requested coded moving picture sequence signal receivedby the second receiving means on the basis of the second coefficientinformation obtained from the series of second picture information ofthe second coded moving picture sequence signal, and the differentialcoefficient information obtained from the differential coded signal toreconstruct the first coded moving picture sequence signal; andoutputting means for inputting the reconstructed first coded movingpicture sequence signal from the merging means to be outputtedtherethrough.

In the above mentioned coded signal separating and merging system, theseparating storage means of the coded signal separating apparatus isoperative to store the differential coded moving picture sequence signalgenerated by the differential coded signal generating means, the firsttransmission means is operative to transmit the second coded movingpicture sequence signal generated by the coded signal converting means,the first receiving means of the coded signal merging apparatus isoperative to receive the second coded moving picture sequence signaltransmitted by the first transmission means, the merging storage meansis operative to store the second coded moving picture sequence signalreceived by the first receiving means, the request signal determiningmeans is operative to determine a request signal for a requesteddifferential coded moving picture sequence signal on the basis of thesecond coded moving picture sequence signal stored by the mergingstorage means, the request signal transmission means is operative totransmit the request signal for the requested differential coded movingpicture sequence signal determined by the request signal determiningmeans, the request signal receiving means of the coded signal separatingapparatus is operative to receive the request signal transmitted by therequest signal transmission means, the separating coded signalextracting means is operative to extract the requested differentialcoded moving picture sequence signal from the separating storage meansin response to the request signal, the second transmission means isoperative to transmit the requested differential coded moving picturesequence signal extracted by the separating coded signal extractingmeans to the coded signal merging apparatus, the second receiving meansof the coded signal merging apparatus is operative to receive therequested differential coded moving picture sequence signal transmittedby the second transmission means from the coded signal separatingapparatus, the merging coded signal extracting means is operative toextract the second coded moving picture sequence signal from the mergingstorage means, and the merging means is operative to merge the secondcoded moving picture sequence signal extracted by the merging codedsignal extracting means with the requested differential coded movingpicture sequence signal received by the second receiving means toreconstruct the first coded moving picture sequence signal.

In the above mentioned coded signal separating and merging system, thecoded signal merging apparatus further includes second coded movingpicture sequence signal decoding means for decoding the second codedmoving picture sequence signal received by the first receiving means.

In the above mentioned coded signal separating and merging system, thecoded signal merging apparatus further includes editing means forcutting and combining component parts of the second coded moving picturesequence signal stored by the merging storage means to generate anedited second coded moving picture sequence signal in a desired size,the request signal determining means is operative to determine a requestsignal for a requested differential coded moving picture sequence signalon the basis of the edited second coded moving picture sequence signalgenerated by the editing means, the request signal transmission means isoperative to transmit the request signal for the requested differentialcoded moving picture sequence signal determined by the request signaldetermining means to the coded signal separating apparatus, theseparating coded signal extracting means of the separating coded signalseparating apparatus is operative to extract the requested differentialcoded moving picture sequence signal from the separating storage meansin response to the request signal, and the merging means is operative tomerge the edited second coded moving picture sequence signal generatedby the editing means with the requested differential coded movingpicture sequence signal received by the second receiving means toreconstruct the first coded moving picture sequence signal in thedesired size.

In the above mentioned coded signal separating and merging system, theseparating storage means of the coded signal separating apparatus isoperative to store the second coded moving picture sequence signalgenerated by the coded signal converting means, the first transmissionmeans is operative to transmit the differential coded moving picturesequence signal generated by the differential coded signal generatingmeans to the coded signal merging apparatus, the first receiving meansof the coded signal merging apparatus is operative to receive thedifferential coded moving picture sequence signal transmitted by thefirst transmission means, the merging storage means is operative tostore the differential coded moving picture sequence signal received bythe first receiving means, request signal determining means is operativeto determine a request signal for a requested second coded movingpicture sequence signal on the basis of the differential coded movingpicture sequence signal stored by the merging storage means, the requestsignal transmission means is operative to transmit the request signalfor the requested second coded moving picture sequence signal determinedby the request signal determining means, the request signal receivingmeans of the coded signal separating apparatus is operative to receivethe request signal transmitted by the request signal transmission means,the separating coded signal extracting means is operative to extract therequested second coded moving picture sequence signal from theseparating storage means in response to the request signal, the secondtransmission means is operative to transmit the requested second codedmoving picture sequence signal extracted by the separating coded signalextracting means to the coded signal merging apparatus, the secondreceiving means of the coded signal merging apparatus is operative toreceive the requested second coded moving picture sequence signaltransmitted by the second transmission means from the coded signalseparating apparatus, the merging coded signal extracting means isoperative to extract the differential coded moving picture sequencesignal stored by the merging storage means, and the merging means isoperative to merge the differential coded moving picture sequence signalextracted by the merging coded signal extracting means with the secondcoded moving picture sequence signal received by the second receivingmeans to reconstruct the first coded moving picture sequence signal.

In the above mentioned coded signal separating and merging system, thefirst transmission means of the coded signal separating apparatus isoperative to transmit the differential coded moving picture sequencesignal by way of broadcasting.

In the above mentioned coded signal separating and merging system, thecoded signal merging apparatus further includes reconstructed firstcoded signal storage means for storing the reconstructed first codedmoving picture sequence signal reconstructed by the merging means.

In the aforesaid coded signal separating and merging system, the codedsignal merging apparatus further includes: decoding means for decodingthe first coded moving picture sequence signal or the second codedmoving picture sequence signal; and merging coded signal convertingmeans for inputting the first coded moving picture sequence signal togenerate the second coded moving picture sequence signal, the firsttransmission means of the coded signal separating apparatus is operativeto transmit the first coded moving picture sequence signal, theseparating storage means is operative to store the differential codedmoving picture sequence signal generated by the differential codedsignal generating means, the first receiving means of the coded signalmerging apparatus is operative to receive the first coded moving picturesequence signal transmitted by the first transmission means from thecoded signal separating apparatus, the decoding means is operative todecode the first coded moving picture sequence signal received by thefirst receiving means, the merging coded signal converting means isoperative to input the first coded moving picture sequence signalreceived by the first receiving means to generate the second codedmoving picture sequence signal, the merging storage means is operativeto store the second coded moving picture sequence signal generated bythe merging coded signal converting means, the request signaldetermining means is operative to determine a request signal for arequested differential coded moving picture sequence signal on the basisof the second coded moving picture sequence signal stored by the mergingstorage means, the request signal transmission means is operative totransmit the request signal for the requested differential coded movingpicture sequence signal determined by the request signal determiningmeans to the coded signal separating apparatus, the request signalreceiving means of the coded signal separating apparatus is operative toreceive the request signal transmitted by the request signaltransmission means from the coded signal merging apparatus, theseparating coded signal extracting means is operative to extract therequested differential coded moving picture sequence signal from theseparating storage means in response to the request signal, the secondtransmission means is operative to transmit the requested differentialcoded moving picture sequence signal extracted by the separating codedsignal extracting means to the coded signal merging apparatus, thesecond receiving means of the coded signal merging apparatus isoperative to receive the requested differential coded moving picturesequence signal transmitted by the second transmission means from thecoded signal separating apparatus, the merging coded signal extractingmeans is operative to extract the second coded moving picture sequencesignal from the merging storage means, and the merging means isoperative to merge the second coded moving picture sequence signalextracted by the merging coded signal extracting means with therequested differential coded moving picture sequence signal received bythe second receiving means to reconstruct the first coded moving picturesequence signal in the desired size.

In the aforesaid coded signal separating and merging system, the codedsignal merging apparatus further includes: decoding means for decodingthe first coded moving picture sequence signal or the second codedmoving picture sequence signal; and merging differential coded signalgenerating means for inputting the first coded moving picture sequencesignal to generate the differential coded moving picture sequencesignal. The first transmission means of the coded signal separatingapparatus is operative to transmit the first coded moving picturesequence signal,

In the above mentioned coded signal separating and merging system, theseparating storage means is operative to store the second coded movingpicture sequence signal generated by the coded signal converting means,the first receiving means of the coded signal merging apparatus isoperative to receive the first coded moving picture sequence signaltransmitted by the first transmission means from the coded signalseparating apparatus, the decoding means is operative to decode thefirst coded moving picture sequence signal received by the firstreceiving means, the merging differential coded signal generating meansis operative to input the first coded moving picture sequence signalreceived by the first receiving means to generate the differential codedmoving picture sequence signal, the merging storage means is operativeto store the differential coded moving picture sequence signal generatedby the merging coded signal converting means, the request signaldetermining means is operative to determine a request signal for arequested second coded moving picture sequence signal on the basis ofthe differential coded moving picture sequence signal stored by themerging storage means, the request signal transmission means isoperative to transmit the request signal for the requested second codedmoving picture sequence signal determined by the request signaldetermining means to the coded signal separating apparatus, the requestsignal receiving means of the coded signal separating apparatus isoperative to receive the request signal transmitted by the requestsignal transmission means from the coded signal merging apparatus, theseparating coded signal extracting means is operative to extract therequested second coded moving picture sequence signal from theseparating storage means in response to the request signal, the secondtransmission means is operative to transmit the requested second codedmoving picture sequence signal extracted by the separating coded signalextracting means to the coded signal merging apparatus, the secondreceiving means of the coded signal merging apparatus is operative toreceive the requested second coded moving picture sequence signaltransmitted by the second transmission means from the coded signalseparating apparatus, the merging coded signal extracting means isoperative to extract the differential coded moving picture sequencesignal from the merging storage means, and the merging means isoperative to merge the differential coded moving picture sequence signalextracted by the merging coded signal extracting means with therequested second coded moving picture sequence signal received by thesecond receiving means to reconstruct the first coded moving picturesequence signal in the desired size.

In accordance with a second aspect of the present invention, there isprovided a coded signal separating apparatus for inputting a first codedmoving picture sequence signal to separate into a second coded movingpicture sequence signal and a differential coded moving picture sequencesignal comprising: inputting means for inputting the first coded movingpicture sequence signal therethrough, the first coded moving picturesequence signal generated as a result of encoding original movingpicture sequence signal and consisting of a series of first pictureinformation having first coefficient information, the first coefficientinformation including a matrix of first coefficients; coded signalconverting means for converting the first coded moving picture sequencesignal inputted through the inputting means to generate the second codedmoving picture sequence signal, the second coded moving picture sequencesignal consisting of a series of second picture information havingsecond coefficient information, the second coefficient informationincluding a matrix of second coefficients, each of the first codedmoving picture sequence signal, and the second coded moving picturesequence signal is in the form of a hierarchical structure including oneor more sequence layers each having a plurality of screens sharingcommon information, one or more picture layers each having a pluralityof slices sharing common information with respect to one of the screens,one or more slice layers each having a plurality of macroblocks withrespect to one of the slices, one or more macroblock layers each havinga plurality of blocks with respect to one of the macroblocks, and one ormore block layers each having block information with respect to one ofthe blocks; differential coded signal generating means for inputting thefirst coded moving picture sequence signal and the second coded movingpicture sequence signal from the coded signal converting means togenerate a differential coded moving picture sequence signal on thebasis of the first coefficient information obtained from the series offirst picture information of the first coded moving picture sequencesignal, and the second coefficient information obtained from the seriesof the second picture information of the second coded moving picturesequence signal, the differential coded moving picture sequence signalbeing a difference between the first coded moving picture sequencesignal and the second coded moving picture sequence signal; separatingstorage means for selectively storing the first coded moving picturesequence signal, the second coded moving picture sequence signal, andthe differential coded moving picture sequence signal; firsttransmission means for selectively transmitting the first coded movingpicture sequence signal, the second coded moving picture sequencesignal, and the differential coded moving picture sequence signal;request signal receiving means for receiving a request signal indicativeof a requested coded moving picture sequence signal to be transmitted,the request signal indicative of the requested coded moving picturesequence signal being determined on the basis of the first coded movingpicture sequence signal, the second coded moving picture sequencesignal, or the differential coded moving picture sequence signal;separating coded signal extracting means for extracting the requestedcoded moving picture sequence signal from the separating storage meansin response to the request signal; and second transmission means fortransmitting the requested coded moving picture sequence signalextracted by the separating coded signal extracting means.

In the aforesaid coded signal separating apparatus, the separatingstorage means is operative to store the differential coded movingpicture sequence signal generated by the differential coded signalgenerating means, the first transmission means is operative to transmitthe second coded moving picture sequence signal generated by the codedsignal converting means, the request signal receiving means is operativeto receive the request signal indicative of a requested differentialcoded moving picture sequence signal to be transmitted, the requestsignal indicative of the requested differential coded moving picturesequence signal being determined on the basis of the second coded movingpicture sequence signal, the separating coded signal extracting means isoperative to extract the requested differential coded moving picturesequence signal from the separating storage means in response to therequest signal, and the second transmission means is operative totransmit the requested differential coded moving picture sequence signalextracted by the separating coded signal extracting means.

In the aforesaid coded signal separating apparatus, the request signalreceiving means is operative to receive the request signal indicative ofthe requested differential coded moving picture sequence signal to betransmitted, the request signal indicative of the requested differentialcoded moving picture sequence signal being determined on the basis of anedited second coded moving picture sequence signal generated by cuttingand combining component parts of the second coded moving picturesequence signal, the separating coded signal extracting means isoperative to extract the requested differential coded moving picturesequence signal from the separating storage means in response to therequest signal, and the second transmission means is operative totransmit the requested differential coded moving picture sequence signalextracted by the separating coded signal extracting means.

In the aforesaid coded signal separating apparatus, the separatingstorage means is operative to store the second coded moving picturesequence signal generated by the coded signal converting means, thefirst transmission means is operative to transmit the differential codedmoving picture sequence signal generated by the differential codedsignal generating means, the request signal receiving means is operativeto receive the request signal indicative of the requested second codedmoving picture sequence signal to be transmitted, the request signalindicative of the requested second coded moving picture sequence signalbeing determined on the basis of the differential coded moving picturesequence signal, the separating coded signal extracting means isoperative to extract the requested second coded moving picture sequencesignal from the separating storage means in response to the requestsignal, and the second transmission means is operative to transmit therequested second coded moving picture sequence signal extracted by theseparating coded signal extracting means.

In the aforesaid coded signal separating apparatus, the firsttransmission means is operative to transmit the differential codedmoving picture sequence signal by way of broadcasting.

In the aforesaid coded signal separating apparatus, the firsttransmission means is operative to transmit the first coded movingpicture sequence signal, the separating storage means is operative tostore the differential coded moving picture sequence signal generated bythe differential coded signal generating means, the request signalreceiving means is operative to receive the request signal indicative ofa requested differential coded moving picture sequence signal to betransmitted, the request signal indicative of the requested differentialcoded moving picture sequence signal being determined on the basis of asecond coded moving picture sequence signal generated in accordance withthe first: coded moving picture sequence signal, the separating codedsignal extracting means is operative to extract the requesteddifferential coded moving picture sequence signal from the separatingstorage means in response to the request signal, and the secondtransmission means is operative to transmit the requested differentialcoded moving picture sequence signal extracted by the separating codedsignal extracting means.

In the aforesaid coded signal separating apparatus, the firsttransmission means is operative to transmit the first coded movingpicture sequence signal, the separating storage means is operative tostore the second coded moving picture sequence signal generated by thecoded signal converting means, the request signal receiving means isoperative to receive the request signal indicative of a requested secondcoded moving picture sequence signal to be transmitted, the requestsignal indicative of the requested second coded moving picture sequencesignal being determined on the basis of a differential coded movingpicture sequence signal generated in accordance with the first codedmoving picture sequence signal, the separating coded signal extractingmeans is operative to extract the requested second coded moving picturesequence signal from the separating storage means in response to therequest signal, and the second transmission means is operative totransmit the requested second coded moving picture sequence signalextracted by the separating coded signal extracting means.

In accordance with a third aspect of the present invention, there isprovided a coded signal merging apparatus for inputting a second codedmoving picture sequence signal and a differential coded moving picturesequence signal to reconstruct a first coded moving picture sequencesignal, the second coded moving picture sequence signal generated as aresult of transcoding the first coded moving picture sequence signal andconsisting of a series of second picture information having secondcoefficient information, the second coefficient information including amatrix of second coefficients, the first coded moving picture sequencesignal generated as a result of encoding original moving picturesequence signal and consisting of a series of first picture informationhaving first coefficient information, the first coefficient informationincluding a matrix of first coefficients, the differential coded movingpicture sequence signal being a difference between the first codedmoving picture sequence signal and the second coded moving picturesequence signal, the differential coded moving picture sequence signalincluding differential coefficient information between the firstcoefficient information and the second coefficient information, each ofthe first coded moving picture sequence signal, the second coded movingpicture sequence signal, and the differential coded moving picturesequence signal is in the form of a hierarchical structure including oneor more sequence layers each having a plurality of screens sharingcommon information, one or more picture layers each having a pluralityof slices sharing common information with respect to one of the screens,one or more slice layers each having a plurality of macroblocks withrespect to one of the slices, one or more macroblock layers each havinga plurality of blocks with respect to one of the macroblocks, and one ormore block layers each having block information with respect to one ofthe blocks, the coded signal merging apparatus comprising: firstreceiving means for receiving a base coded moving picture sequencesignal, the base coded moving picture sequence signal being any one ofthe first coded moving picture sequence signal, the second coded movingpicture sequence signal, and the differential coded moving picturesequence signal; merging storage means for storing the base coded movingpicture sequence signal received by the first receiving means; requestsignal determining means for determining a request signal for arequested coded moving picture sequence signal on the basis of the basecoded moving picture sequence signal stored by the merging storagemeans; request signal transmission means for transmitting the requestsignal for the requested coded moving picture sequence signal determinedby the request signal determining means; second receiving means forreceiving the requested coded moving picture sequence signal; mergingcoded signal extracting means for extracting the base coded movingpicture sequence signal from the merging storage means; merging meansfor merging the base coded moving picture sequence signal extracted bythe merging coded signal extracting means with the requested codedmoving picture sequence signal received by the second receiving means toreconstruct the first coded moving picture sequence signal on the basisof the second coefficient information obtained from the series of secondpicture information of the second coded moving picture sequence signal,and the differential coefficient information obtained from thedifferential coded signal; and outputting means for inputting thereconstructed first coded moving picture sequence signal from themerging means to be outputted therethrough.

In the aforesaid coded signal merging apparatus, the first receivingmeans is operative to receive the second coded moving picture sequencesignal, the merging storage means is operative to store the second codedmoving picture sequence signal received by the first receiving means,the request signal determining means is operative to determine a requestsignal for a requested differential coded moving picture sequence signalon the basis of the second coded moving picture sequence signal storedby the merging storage means, the request signal transmission means isoperative to transmit a request signal for the requested differentialcoded moving picture sequence signal determined by the request signaldetermining means, the second receiving means is operative to receivethe requested differential coded moving picture sequence signal, themerging coded signal extracting means is operative to extract the secondcoded moving picture sequence signal from the merging storage means, andthe merging means is operative to merge the second coded moving picturesequence signal extracted by the merging coded signal extracting meanswith the requested differential coded moving picture sequence signalreceived by the second receiving means to reconstruct the first codedmoving picture sequence signal.

The aforesaid coded signal merging apparatus may further comprise secondcoded moving picture sequence signal decoding means for decoding thesecond coded moving picture sequence signal received by the firstreceiving means.

The aforesaid coded signal merging apparatus may further compriseediting means for cutting and combining component parts of the secondcoded moving picture sequence signal stored by the merging storage meansto generate an edited second coded moving picture sequence signal in adesired size, in which the request signal determining means is operativeto determine a request signal for a requested differential coded movingpicture sequence signal on the basis of the edited second coded movingpicture sequence signal generated by the editing means, the requestsignal transmission means is operative to transmit the request signalfor the requested differential coded moving picture sequence signaldetermined by the request signal determining means, and the mergingmeans is operative to merge the edited second coded moving picturesequence signal generated by the editing means with the requesteddifferential coded moving picture sequence signal received by the secondreceiving means to reconstruct the first coded moving picture sequencesignal in the desired size.

In the aforesaid coded signal merging apparatus, the first receivingmeans is operative to receive the differential coded moving picturesequence signal, the merging storage means is operative to store thedifferential coded moving picture sequence signal received by the firstreceiving means, the request signal determining means is operative todetermine a request signal for a requested second coded moving picturesequence signal on the basis of the differential coded moving picturesequence signal stored by the merging storage means, the request signaltransmission means is operative to transmit the request signal for therequested second coded moving picture sequence signal determined by therequest signal determining means, the second receiving means isoperative to receive the requested second coded moving picture sequencesignal, the merging coded signal extracting means is operative toextract the differential coded moving picture sequence signal stored bythe merging storage means, and the merging means is operative to mergethe differential coded moving picture sequence signal extracted by themerging coded signal extracting means with the second coded movingpicture sequence signal received by the second receiving means toreconstruct the first coded moving picture sequence signal.

In the aforesaid coded signal merging apparatus, the first receivingmeans is operative to receive the differential coded moving picturesequence signal by way of broadcasting.

The aforesaid coded signal merging apparatus may further comprisereconstructed first coded signal storage means for storing thereconstructed first coded moving picture sequence signal reconstructedby the merging means.

The aforesaid coded signal merging apparatus may further comprise:decoding means for decoding the first coded moving picture sequencesignal or the second coded moving picture sequence signal; and mergingcoded signal converting means for inputting the first coded movingpicture sequence signal to generate the second coded moving picturesequence signal, in which the first receiving means is operative toreceive the first coded moving picture sequence signal, the decodingmeans is operative to decode the first coded moving picture sequencesignal received by the first receiving means, the merging coded signalconverting means is operative to input the first coded moving picturesequence signal received by the first receiving means to generate thesecond coded moving picture sequence signal, the merging storage meansis operative to store the second coded moving picture sequence signalgenerated by the merging coded signal converting means, the requestsignal determining means is operative to determine a request signal fora requested differential coded moving picture sequence signal on thebasis of the second coded moving picture sequence signal stored by themerging storage means, the request signal transmission means isoperative to transmit the request signal for the requested differentialcoded moving picture sequence signal determined by the request signaldetermining means, the second receiving means is operative to receivethe requested differential coded moving picture sequence signal, themerging coded signal extracting means is operative to extract the secondcoded moving picture sequence signal from the merging storage means, andthe merging means is operative to merge the second coded moving picturesequence signal extracted by the merging coded signal extracting meanswith the requested differential coded moving picture sequence signalreceived by the second receiving means to reconstruct the first codedmoving picture sequence signal in the desired size.

The aforesaid coded signal merging apparatus may further comprise:decoding means for decoding the first coded moving picture sequencesignal or the second coded moving picture sequence signal; and mergingdifferential coded signal generating means for inputting the first codedmoving picture sequence signal to generate the differential coded movingpicture sequence signal, the first receiving means is operative toreceive the first coded moving picture sequence signal, the decodingmeans is operative to decode the first coded moving picture sequencesignal received by the first receiving means, the merging differentialcoded signal generating means is operative to input the first codedmoving picture sequence signal received by the first receiving means togenerate the differential coded moving picture sequence signal, themerging storage means is operative to store the differential codedmoving picture sequence signal generated by the merging coded signalconverting means, the request signal determining means is operative todetermine a request signal for a requested second coded moving picturesequence signal on the basis of the differential coded moving picturesequence signal stored by the merging storage means, the request signaltransmission means is operative to transmit the request signal for therequested second coded moving picture sequence signal determined by therequest signal determining means, the second receiving means isoperative to receive the requested second coded moving picture sequencesignal, the merging coded signal extracting means is operative toextract the differential coded moving picture sequence signal from themerging storage means, and the merging means is operative to merge thedifferential coded moving picture sequence signal extracted by themerging coded signal extracting means with the requested second codedmoving picture sequence signal received by the second receiving means toreconstruct the first coded moving picture sequence signal in thedesired size.

In accordance with a fourth aspect of the present invention, there isprovided a multi-output coded signal separating apparatus for inputtinga first coded moving picture sequence signal to separate into aplurality of second coded moving picture sequence signals and aplurality of differential coded moving picture sequence signalscomprising: a plurality of coded signal separating units including a 1stcoded signal separating unit up to a m-th coded signal separating unitwherein m is an integer not less than two; the 1st coded signalseparating unit being operative to input the first coded moving picturesequence signal to separate into a 1st second coded moving picturesequence signal and a 1st differential coded moving picture sequencesignal, the 1st differential coded moving picture sequence signal beinga difference between the first coded moving picture sequence signal andthe 1st second coded moving picture sequence signal, and the i-th codedsignal separating unit being operative to input an (i−1)-th second codedmoving picture sequence signal to separate into an i-th second codedmoving picture sequence signal and an i-th differential coded movingpicture sequence signal, the i-th differential coded moving picturesequence signal being a difference between the (i−1)-th second codedmoving picture sequence signal and the i-th second coded moving picturesequence signal wherein i is an integer equal to or less than m.

The aforesaid 1st coded signal separating unit includes: 1st inputtingmeans for inputting the first coded moving picture sequence signaltherethrough, the first coded moving picture sequence signal generatedas a result of encoding original moving picture sequence signal andconsisting of a series of first picture information having firstcoefficient information, the first coefficient information including amatrix of first coefficients; 1st coded signal converting means forconverting the first coded moving picture sequence signal inputtedthrough the 1st inputting means to generate a 1st second coded movingpicture sequence signal, the 1st second coded moving picture sequencesignal consisting of a series of 1st second picture information having1st second coefficient information, the 1st second coefficientinformation including a matrix of 1st second coefficients, each of thefirst coded moving picture sequence signal, and the 1st second codedmoving picture sequence signal is in the form of a hierarchicalstructure including one or more sequence layers each having a pluralityof screens sharing common information, one or more picture layers eachhaving a plurality of slices sharing common information with respect toone of the screens, one or more slice layers each having a plurality ofmacroblocks with respect to one of the slices, one or more macroblocklayers each having a plurality of blocks with respect to one of themacroblocks, and one or more block layers each having block informationwith respect to one of the blocks; 1st differential coded signalgenerating means for inputting the first coded moving picture sequencesignal and the 1st second coded moving picture sequence signal from the1st coded signal converting means to generate a 1st differential codedmoving picture sequence signal on the basis of the first coefficientinformation obtained from the series of first picture information of thefirst coded moving picture sequence signal, and the 1st secondcoefficient information obtained from the series of the 1st secondpicture information of the 1st second coded moving picture sequencesignal, the 1st differential coded moving picture sequence signal beinga difference between the first coded moving picture sequence signal andthe 1st second coded moving picture sequence signal; 1st separatingstorage means for selectively storing the first coded moving picturesequence signal, the 1st second coded moving picture sequence signal,and the 1st differential coded moving picture sequence signal; 1st firsttransmission means for selectively transmitting the first coded movingpicture sequence signal, the 1st second coded moving picture sequencesignal, and the 1st differential coded moving picture sequence signal;1st request signal receiving means for receiving a request signalindicative of a requested coded moving picture sequence signal to betransmitted, the request signal indicative of the requested coded movingpicture sequence signal being determined on the basis of the first codedmoving picture sequence signal, the 1st second coded moving picturesequence signal, or the 1st differential coded moving picture sequencesignal; 1st separating coded signal extracting means for extracting therequested coded moving picture sequence signal from the 1st separatingstorage means in response to the request signal; and 1st secondtransmission means for transmitting the requested coded moving picturesequence signal extracted by the 1st separating coded signal extractingmeans.

The aforesaid i-th coded signal separating unit includes: i-th inputtingmeans for inputting the (i−1)-th second coded moving picture sequencesignal therethrough from the (i−1)-th coded signal separating unit, the(i−1)-th second coded moving picture sequence signal generated as aresult of encoding original moving picture sequence signal andconsisting of a series of (i−1)-th second picture information having(i−1)-th second coefficient information, the (i−1)-th second coefficientinformation including a matrix of (i−1)-th second coefficients; i-thcoded signal converting means for converting the (i−1)-th second codedmoving picture sequence signal inputted through the i-th inputting meansto generate the i-th second coded moving picture sequence signal, thei-th second coded moving picture sequence signal consisting of a seriesof i-th second picture information having i-th second coefficientinformation, the i-th second coefficient information including a matrixof i-th second coefficients, each of the (i−1)-th second coded movingpicture sequence signal, and the i-th second coded moving picturesequence signal is in the form of a hierarchical structure including oneor more sequence layers each having a plurality of screens sharingcommon information, one or more picture layers each having a pluralityof slices sharing common information with respect to one of the screens,one or more slice layers each having a plurality of macroblocks withrespect to one of the slices, one or more macroblock layers each havinga plurality of blocks with respect to one of the macroblocks, and one ormore block layers each having block information with respect to one ofthe blocks; i-th differential coded signal generating means forinputting the (i−1)-th second coded moving picture sequence signal andthe i-th second coded moving picture sequence signal from the i-th codedsignal converting means to generate an i-th differential coded movingpicture sequence signal on the basis of the (i−1)-th second coefficientinformation obtained from the series of (i−1)-th second pictureinformation of the (i−1)-th second coded moving picture sequence signal,and the i-th second coefficient information obtained from the series ofthe i-th second picture information of the i-th second coded movingpicture sequence signal, the i-th differential coded moving picturesequence signal being a difference between the (i−1)-th second codedmoving picture sequence signal and the i-th second coded moving picturesequence signal; i-th separating storage means for selectively storingthe (i−1)-th second coded moving picture sequence signal, the i-thsecond coded moving picture sequence signal, and the i-th differentialcoded moving picture sequence signal; i-th first transmission means forselectively transmitting the (i−1)-th second coded moving picturesequence signal, the i-th second coded moving picture sequence signal,and the i-th differential coded moving picture sequence signal; i-threquest signal receiving means for receiving a request signal indicativeof a requested coded moving picture sequence signal to be transmitted,the request signal indicative of the requested coded moving picturesequence signal being determined on the basis of the (i−1)-th secondcoded moving picture sequence signal, the i-th second coded movingpicture sequence signal, or the i-th differential coded moving picturesequence signal; i-th separating coded signal extracting means forextracting the requested coded moving picture sequence signal from thei-th separating storage means in response to the request signal; andi-th second transmission means for transmitting the requested codedmoving picture sequence signal extracted by the i-th separating codedsignal extracting means.

In accordance with a fifth aspect of the present invention, there isprovided a multi-input coded signal merging apparatus for inputting aplurality of second coded moving picture sequence signals and aplurality of differential coded moving picture sequence signals toreconstruct a first coded moving picture sequence signal comprising: aplurality of the coded signal merging units including a 1st coded signalmerging unit up to a n-th coded signal merging unit wherein n is aninteger not less than two, in which the i-th coded signal merging unitis operative to input an i-th second coded moving picture sequencesignal and an i-th differential coded moving picture sequence signal toreconstruct an (i−1)-th second coded moving picture sequence signalwherein i is an integer equal to or less than n, the i-th second codedmoving picture sequence signal generated as a result of transcoding the(i−1)-th second coded moving picture sequence signal and consisting of aseries of i-th second picture information having i-th second coefficientinformation, the i-th second coefficient information including a matrixof i-th second coefficients, the (i−1)-th second coded moving picturesequence signal generated as a result of encoding original movingpicture sequence signal and consisting of a series of (i−1)-th secondpicture information having (i−1)-th second coefficient information, the(i−1)-th second coefficient information including a matrix of (i−1)-thsecond coefficients, the i-th differential coded moving picture sequencesignal being a difference between the i-th second coded moving picturesequence signal and the (i−1)-th second coded moving picture sequencesignal, the i-th differential coded moving picture sequence signalincluding i-th differential coefficient information between the i-thsecond coefficient information and the (i−1)-th second coefficientinformation, each of the i-th second coded moving picture sequencesignal, the (i−1)-th second coded moving picture sequence signal, andthe i-th differential coded moving picture sequence signal is in theform of a hierarchical structure including one or more sequence layerseach having a plurality of screens sharing common information, one ormore picture layers each having a plurality of slices sharing commoninformation with respect to one of the screens, one or more slice layerseach having a plurality of macroblocks with respect to one of theslices, one or more macroblock layers each having a plurality of blockswith respect to one of the macroblocks, and one or more block layerseach having block information with respect to one of the blocks, and the1st coded signal merging unit is operative to input the 1st second codedmoving picture sequence signal and the 1st differential coded movingpicture sequence signal to reconstruct the first coded moving picturesequence signal.

The aforesaid i-th coded signal merging unit includes: i-th firstreceiving means for receiving a base coded moving picture sequencesignal, the base coded moving picture sequence signal being any one ofthe i-th second coded moving picture sequence signal, the (i−1)-thsecond coded moving picture sequence signal, and the i-th differentialcoded moving picture sequence signal; i-th merging storage means forstoring the base coded moving picture sequence signal received by thei-th first receiving means; i-th request signal determining means fordetermining a request signal for a requested coded moving picturesequence signal on the basis of the base coded moving picture sequencesignal stored by the i-th merging storage means; i-th request signaltransmission means for transmitting the request signal for the requestedcoded moving picture sequence signal determined by the i-th requestsignal determining means; i-th second receiving means for receiving therequested coded moving picture sequence signal; i-th merging codedsignal extracting means for extracting the base coded moving picturesequence signal from the i-th merging storage means; i-th merging meansfor merging the base coded moving picture sequence signal extracted bythe i-th merging coded signal extracting means with the requested codedmoving picture sequence signal received by the i-th second receivingmeans to reconstruct the (i−1)-th second coded moving picture sequencesignal on the basis of the second coefficient information obtained fromthe series of second picture information of the i-th second coded movingpicture sequence signal, and the i-th differential coefficientinformation obtained from the i-th differential bit stream; and i-thoutputting means for inputting the reconstructed i-th second codedmoving picture sequence signal from the i-th merging means to beoutputted therethrough.

The aforesaid 1st coded signal merging unit includes: 1st firstreceiving means for receiving a base coded moving picture sequencesignal, the base coded moving picture sequence signal being any one ofthe first coded moving picture sequence signal, the 1st second codedmoving picture sequence signal, and the 1st differential coded movingpicture sequence signal; 1st merging storage means for storing the basecoded moving picture sequence signal received by the 1st first receivingmeans; 1st request signal determining means for determining a requestsignal for a requested coded moving picture sequence signal on the basisof the base coded moving picture sequence signal stored by the 1stmerging storage means; 1st request signal transmission means fortransmitting the request signal for the requested coded moving picturesequence signal determined by the 1st request signal determining means;1st second receiving means for receiving the requested coded movingpicture sequence signal; 1st merging coded signal extracting means forextracting the base coded moving picture sequence signal from the 1stmerging storage means; 1st merging means for merging the base codedmoving picture sequence signal extracted by the 1st merging coded signalextracting means with the requested coded moving picture sequence signalreceived by the 1st second receiving means to reconstruct the firstcoded moving picture sequence signal on the basis of the 1st secondcoefficient information obtained from the series of second pictureinformation of the 1st second coded moving picture sequence signal, andthe 1st differential coefficient information obtained from the 1stdifferential coded signal; and 1st outputting means for inputting thereconstructed first coded moving picture sequence signal from the 1 stmerging means to be outputted therethrough.

In the above mentioned the i-th coded signal separating unit, the i-thseparating storage means is operative to store the (i−1)-th differentialcoded moving picture sequence signal generated by the i-th differentialcoded signal generating means, the i-th first transmission means isoperative to transmit the (i−1)-th second coded moving picture sequencesignal generated by the i-th coded signal converting means, the i-threquest signal receiving means is operative to receive the requestsignal indicative of a requested (i−1)-th differential coded movingpicture sequence signal to be transmitted, the request signal indicativeof the requested (i−1)-th differential coded moving picture sequencesignal being determined on the basis of the (i−1)-th second coded movingpicture sequence signal, the i-th separating coded signal extractingmeans is operative to extract the requested (i−1)-th differential codedmoving picture sequence signal from the i-th separating storage means inresponse to the request signal, and the i-th second transmission meansis operative to transmit the requested (i−1)-th differential codedmoving picture sequence signal extracted by the i-th separating codedsignal extracting means, and the aforesaid multi-output coded signalseparating apparatus is operative to input a first coded moving picturesequence signal to separate into a plurality of second coded movingpicture sequence signals and a plurality of differential coded movingpicture sequence signals.

In the above described the i-th coded signal separating unit, the i-thfirst receiving means is operative to receive the i-th second codedmoving picture sequence signal, the i-th merging storage means isoperative to store the i-th second coded moving picture sequence signalreceived by the i-th first receiving means, the i-th request signaldetermining means is operative to determine a request signal for arequested differential coded moving picture sequence signal on the basisof the i-th second coded moving picture sequence signal stored by thei-th merging storage means, the i-th request signal transmission meansis operative to transmit the request signal for the requesteddifferential coded moving picture sequence signal determined by the i-threquest signal determining means, the i-th second receiving means isoperative to receive the requested differential coded moving picturesequence signal, the i-th merging coded signal extracting means isoperative to extract the i-th second coded moving picture sequencesignal from the i-th merging storage means, and the i-th merging meansis operative to merge the i-th second coded moving picture sequencesignal extracted by the i-th merging coded signal extracting means withthe requested differential coded moving picture sequence signal receivedby the i-th second receiving means to reconstruct the (i−1)-th secondcoded moving picture sequence signal wherein the 0-th second codedmoving picture sequence signal is the first coded moving picturesequence signal.

In accordance with a sixth aspect of the present invention, there isprovided a coded signal separating and merging system comprising: amulti-output coded signal separating apparatus for inputting a firstcoded moving picture sequence signal to separate into a plurality ofsecond coded moving picture sequence signals and a plurality ofdifferential coded moving picture sequence signals; and a multi-inputcoded signal merging apparatus for inputting a plurality of second codedmoving picture sequence signals and a plurality of differential codedmoving picture sequence signals to reconstruct the first coded movingpicture sequence signal. The above multi-output coded signal separatingapparatus includes: a plurality of coded signal separating unitsincluding a 1st coded signal separating unit up to a m-th coded signalseparating unit wherein m is an integer not less than two. The abovemulti-input coded signal merging apparatus includes: a plurality ofcoded signal merging units including a 1st coded signal merging unit upto a n-th coded signal merging unit wherein n is an integer not lessthan two and equal to or less than the m.

The above i-th coded signal separating unit includes: i-th inputtingmeans for inputting an (i−1)-th second coded moving picture sequencesignal therethrough from the (i−1)-th coded signal separating unit, the(i−1)-th second coded moving picture sequence signal generated as aresult of encoding original moving picture sequence signal andconsisting of a series of (i−1)-th second picture information having(i−1)-th second coefficient information, the (i−1)-th second coefficientinformation including a matrix of (i−1)-th second coefficients wherein iis an integer equal to or less than m, and 0-th second coded movingpicture sequence signal is the first coded moving picture sequencesignal; i-th coded signal converting means for converting the (i−1)-thsecond coded moving picture sequence signal inputted through the i-thinputting means to generate an i-th second coded moving picture sequencesignal, the i-th second coded moving picture sequence signal consistingof a series of i-th second picture information having i-th secondcoefficient information, the i-th second coefficient informationincluding a matrix of second coefficients, each of the (i−1)-th secondcoded moving picture sequence signal, and the i-th second coded movingpicture sequence signal is in the form of a hierarchical structureincluding one or more sequence layers each having a plurality of screenssharing common information, one or more picture layers each having aplurality of slices sharing common information with respect to one ofthe screens, one or more slice layers each having a plurality ofmacroblocks with respect to one of the slices, one or more macroblocklayers each having a plurality of blocks with respect to one of themacroblocks, and one or more block layers each having block informationwith respect to one of the blocks; i-th differential coded signalgenerating means for inputting the (i−1)-th second coded moving picturesequence signal and the i-th second coded moving picture sequence signalfrom the i-th coded signal converting means to generate an i-thdifferential coded moving picture sequence signal on the basis of the(i−1)-th second coefficient information obtained from the series of(i−1)-th second picture information of the (i−1)-th second coded movingpicture sequence signal, and the i-th second coefficient informationobtained from the series of the i-th second picture information of thei-th second coded moving picture sequence signal, the i-th differentialcoded moving picture sequence signal being a difference between the(i−1)-th second coded moving picture sequence signal and the i-th secondcoded moving picture sequence signal; i-th separating storage means forselectively storing the (i−1)-th second coded moving picture sequencesignal, the i-th second coded moving picture sequence signal, and thei-th differential coded moving picture sequence signal; and i-th firsttransmission means for selectively transmitting the (i−1)-th secondcoded moving picture sequence signal, the i-th second coded movingpicture sequence signal, and the i-th differential coded moving picturesequence signal to the i-th coded signal merging unit.

The above i-th coded signal merging unit includes: i-th first receivingmeans for receiving a base coded moving picture sequence signal from thei-th coded signal separating unit or the (i+1)-th coded signal mergingunit 6200 i+1, the base coded moving picture sequence signal being anyone of the (i−1)-th second coded moving picture sequence signal, thei-th second coded moving picture sequence signal, and the i-thdifferential coded moving picture sequence signal; i-th merging storagemeans for storing the base coded moving picture sequence signal receivedby the i-th first receiving means; i-th request signal determining meansfor determining a request signal for a requested coded moving picturesequence signal on the basis of the base coded moving picture sequencesignal stored by the i-th merging storage means; and i-th request signaltransmission means for transmitting the request signal for the requestedcoded moving picture sequence signal determined by the i-th requestsignal determining means to the i-th coded signal separating unit.

The above i-th coded signal separating unit further includes: i-threquest signal receiving means for receiving the request signaltransmitted by the i-th request signal transmission means from the i-thcoded signal merging unit; i-th separating coded signal extracting meansfor extracting the requested coded moving picture sequence signal fromthe i-th separating storage means in response to the request signal; andi-th second transmission means for transmitting the requested codedmoving picture sequence signal extracted by the i-th separating codedsignal extracting means to the i-th coded signal merging unit. The abovei-th coded signal merging unit includes: i-th second receiving means forreceiving the requested coded moving picture sequence signal transmittedby the i-th second transmission means from the i-th coded signalseparating unit; i-th merging coded signal extracting means forextracting the base coded moving picture sequence signal from the i-thmerging storage means; i-th merging means for merging the base codedmoving picture sequence signal extracted by the i-th merging codedsignal extracting means with the requested coded moving picture sequencesignal received by the i-th second receiving means on the basis of thei-th second coefficient information obtained from the series of secondpicture information of the i-th second coded moving picture sequencesignal, and the i-th differential coefficient information obtained fromthe differential coded signal to reconstruct the (i−1)-th second codedmoving picture sequence signal; and i-th outputting means for inputtingthe reconstructed (i−1)-th second coded moving picture sequence signalfrom the i-th merging means to be outputted therethrough.

In the aforesaid coded signal separating and merging system, the i-thseparating storage means of the i-th coded signal separating unit isoperative to store the i-th differential coded moving picture sequencesignal generated by the i-th differential coded signal generating means,the i-th first transmission means is operative to transmit the i-thsecond coded moving picture sequence signal generated by the i-th codedsignal converting means, the i-th first receiving means of the i-thcoded signal merging unit is operative to receive the i-th second codedmoving picture sequence signal (i+1)-th coded signal merging unit, thei-th merging storage means is operative to store the i-th second codedmoving picture sequence signal received by the i-th first receivingmeans, the i-th request signal determining means is operative todetermine a request signal for a requested differential coded movingpicture sequence signal on the basis of the i-th second coded movingpicture sequence signal stored by the i-th merging storage means, thei-th request signal transmission means is operative to transmit therequest signal for the requested differential coded moving picturesequence signal determined by the i-th request signal determining means,the i-th request signal receiving means of the i-th coded signalseparating unit is operative to receive the request signal transmittedby the i-th request signal transmission means, the i-th separating codedsignal extracting means is operative to extract the requesteddifferential coded moving picture sequence signal from the i-thseparating storage means in response to the request signal, the i-thsecond transmission means is operative to transmit the requesteddifferential coded moving picture sequence signal extracted by the i-thseparating coded signal extracting means to the i-th coded signalmerging unit, the i-th second receiving means of the i-th coded signalmerging unit is operative to receive the requested differential codedmoving picture sequence signal transmitted by the i-th secondtransmission means from the i-th coded signal separating unit, the i-thmerging coded signal extracting means is operative to extract the i-thsecond coded moving picture sequence signal from the i-th mergingstorage means, and the i-th merging means is operative to merge the i-thsecond coded moving picture sequence signal extracted by the i-thmerging coded signal extracting means with the requested differentialcoded moving picture sequence signal received by the i-th secondreceiving means to reconstruct the first coded moving picture sequencesignal.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention and many of the advantages thereof will be betterunderstood from the following detailed description when considered inconnection with the accompanying drawings, wherein:

FIG. 1 is a block diagram of a first preferred embodiment of a bitstream separating and merging system 1000 according to the presentinvention;

FIG. 2 is a block diagram of a preferred embodiment of a bit streamseparating apparatus 1100 according to the present invention;

FIG. 3 is a data structural diagram showing the hierarchical structureof a differential bit stream;

FIG. 4 is a block diagram of a preferred embodiment of a bit streammerging apparatus 1200 according to the present invention;

FIG. 5 is a diagram showing renderings of an environment in which apreferred embodiment of a bit stream separating and merging system 1000according to the present invention is utilized;

FIG. 6 is a block diagram of a second preferred embodiment of a bitstream separating and merging system 2000 according to the presentinvention;

FIG. 7 is a block diagram of a third preferred embodiment of a bitstream separating and merging system 3000 according to the presentinvention;

FIG. 8 is a block diagram of a fourth preferred embodiment of a bitstream separating and merging system 4000 according to the presentinvention;

FIG. 9 is a block diagram of a fifth preferred embodiment of a bitstream separating and merging system 5000 according to the presentinvention;

FIG. 10 is a block diagram of a sixth preferred embodiment of a bitstream separating and merging system 6000 according to the presentinvention;

FIG. 11 is a block diagram of a seventh preferred embodiment of a bitstream separating and merging system 7000 according to the presentinvention;

FIG. 12 is a block diagram of a multi-output bit stream separatingapparatus 7100 according to the present invention;

FIG. 13 is a block diagram of a multi-input bit stream merging apparatus7200 according to the present invention;

FIG. 14 is a schematic block diagram showing a first conventionaltranscoder 50;

FIG. 15 is a flowchart showing the flow of the rate control operation ofMPEG-2 performed by the first conventional transcoder 50 shown in FIG.14;

FIG. 16 is a schematic block diagram showing a second conventionaltranscoder 60;

FIG. 17 is a flowchart showing the flow of the rate control operation ofMPEG-2 performed by the second conventional transcoder 60 shown in FIG.16;

FIG. 18 is a schematic block diagram showing a third conventionaltranscoder 80;

FIG. 19 is a flowchart showing the flow of the rate control operation ofMPEG-2 performed by the third conventional transcoder 80 shown in FIG.18;

FIG. 20 is a schematic block diagram showing a fourth conventionaltranscoder 90.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Throughout the following detailed description, similar referencecharacters refer to similar elements in all figures of the drawings.

I. First Embodiment of Bit Stream Separating and Merging System 1000

Referring to FIG. 1 of the drawings, there is shown a first preferredembodiment of a bit stream separating and merging system 1000 accordingto the present invention.

The first preferred embodiment of the bit stream separating and mergingsystem 1000 according to the present invention is shown in FIG. 1 ascomprising a bit stream separating apparatus 1100 and a bit streammerging apparatus 1200.

Some moving picture information is not required to have a high picturequality. Demo video moving picture information, for instance, isrequired to be promptly transmitted to audiences. Upon receiving thedemo video moving picture information, the audiences can preview thedemo video moving picture information as long as the demo video movingpicture information has a minimum picture quality.

In the first preferred embodiment of the bit stream separating andmerging system 1000 according to the present invention, the bit streamseparating apparatus 1100 is operated to input an original MPEG-2 bitstream to separate into a transcoded MPEG-2 bit stream and adifferential bit stream, and then store the differential bit stream inthe bit stream separating apparatus 1100 and transmit only thetranscoded MPEG-2 bit stream to the bit stream merging apparatus 1200.The bit rate of the transcoded MPEG-2 bit stream is lower than that ofthe original MPEG-2 bit stream, thereby making it possible for the bitstream separating apparatus 1100 to transmit the transcoded MPEG-2 bitstream to the bit stream merging apparatus 1200 faster than the originalMPEG-2 bit stream.

The bit stream merging apparatus 1200, on the other hand, can receivethe transcoded MPEG-2 bit stream to reproduce moving picture informationof a low picture quality, for instance, to be used as demo video movingpicture information. If a user decides to watch the moving pictureinformation of a high quality, the bit stream merging apparatus 1200 cantransmit a request signal for a differential bit stream corresponding tothe transcoded MPEG-2 bit stream already received to the bit streamseparating apparatus 2100. In response to the request for the requesteddifferential bit stream, the bit stream separating apparatus 1100 isoperated to extract the requested differential bit stream from among thestored bit streams, and transmit the requested differential bit streamto the bit stream merging apparatus 1200.

Upon receiving the requested differential bit stream, the bit streammerging apparatus 1200 is operated to merge the transcoded MPEG-2 bitstream already received and the requested differential bit stream justreceived to reconstruct the original MPEG-2 bit stream.

This means that a user may receive the transcoded MPEG-2 bit stream at abit rate lower than that of the original MPEG-2 bit stream to reproducelow-quality moving picture information to be previewed, and laterreceive the differential bit stream to be merged with the transcodedMPEG-2 bit stream earlier received to reproduce high-quality movingpicture information to be watched.

Once the transcoded MPEG-2 bit stream has already been arrived, the bitstream separating apparatus 1100 is not required to retransmit theoriginal MPEG-2 bit stream but the differential bit stream alone,thereby effectively utilize the transcoded MPEG-2 bit streams and thetransmitting paths.

The constructions of the bit stream separating apparatus 1100 and thebit stream merging apparatus 1200 will be described in detail beforedescribing the operation of the bit stream separating and merging system1000.

I-A Bit Stream Separating Apparatus 1100

Referring to FIG. 2 of the drawings, there is shown a preferredembodiment of a bit stream separating apparatus 1100. As shown in FIG.2, the bit stream separating apparatus 1100 comprises an inputtingterminal a1, bit stream converting means 111, differential bit streamgenerating means 112, separating storage means 120, first transmissionmeans 141, request signal receiving means 142, bit stream extractingmeans 130, second transmission means 143, and outputting interfacesOUT1, OUT2. The bit stream converting means 111, differential bit streamgenerating means 112 collectively constitute a separating means 110 for:inputting an original MPEG-2 bit stream to separate into a transcodedMPEG-2 bit stream and a differential bit stream. The first transmissionmeans 141, the request signal receiving means 142, and the secondtransmission means 143 collectively constitute a communication means 140for transmitting and receiving bit streams and signals. The bit streamseparating apparatus 1100 constitutes the coded signal separatingapparatus according to the present invention. The inputting terminal a1,the bit stream converting means 111, the differential bit streamgenerating means 112, the bit stream extracting means 130 respectivelyconstitute inputting means, coded signal converting means, differentialcoded signal generating means, and separating coded signal extractingmeans according to the present invention.

The inputting terminal a1 is adapted to input an original MPEG-2 bitstream therethrough. The original MPEG-2 bit stream is generated as aresult of encoding original moving picture sequence signal andconsisting of a series of first picture information having firstcoefficient information. The first coefficient information includes amatrix of first coefficients.

The bit stream converting means 111 is adapted to input the originalMPEG-2 bit stream through the inputting terminal a1 and convert theoriginal MPEG-2 bit stream inputted through the inputting terminal a1 togenerate a transcoded MPEG-2 bit stream. The bit stream converting means111 can output the transcoded MPEG-2 bit stream thus generated to thedifferential bit stream generating means 112 and the separating storagemeans 120 through an interface out1.

In the bit stream separating apparatus 1100 according to the presentinvention, the bit stream converting means 111 may directly transmit thetranscoded MPEG-2 bit stream to the first transmission means 141 throughan interface out1. Furthermore, the bit stream converting means 111 mayoutput the original MPEG-2 bit stream inputted through the inputtingmeans a1 to the differential bit stream generating means 112.

The transcoded MPEG-2 bit stream consists of a series of second pictureinformation having second coefficient information. The secondcoefficient information includes a matrix of second coefficients. Eachof the original MPEG-2 bit stream, and the transcoded MPEG-2 bit streamis in the form of a hierarchical structure including one or moresequence layers each having a plurality of screens sharing commoninformation, one or more picture layers each having a plurality ofslices sharing common information with respect to one of the screens,one or more slice layers each having a plurality of macroblocks withrespect to one of the slices, one or more macroblock layers each havinga plurality of blocks with respect to one of the macroblocks, and one ormore block layers each having block information with respect to one ofthe blocks.

The differential bit stream generating means 112 is adapted to input theoriginal MPEG-2 bit stream and the transcoded MPEG-2 bit stream from thebit stream converting means 111 to generate a differential bit stream onthe basis of the first coefficient information obtained from the seriesof first picture information of the original MPEG-2 bit stream, and thesecond coefficient information obtained from the series of the secondpicture information of the transcoded MPEG-2 bit stream. Thedifferential bit stream generating means 112 is adapted to output thedifferential bit stream thus generated to the separating storage means120 through an interface out2. Here, the differential bit stream isintended to mean a difference between the original MPEG-2 bit stream andthe transcoded MPEG-2 bit stream.

More specifically, the differential bit stream, thus generated by thedifferential bit stream generating means 112, is in the form of thehierarchical structure including the sequence layers, the picturelayers, the slice layers, the macroblock layers, and the block layers,similar to the original MPEG-2 bit streams and the transcoded MPEG-2 bitstreams as shown in FIG. 3. The differential bit stream starts from asequence header of the sequence layer. Followed by the sequence header,picture layer data elements continue for the number of picturescontained in the sequence layer. The picture layer data elementcomprises a picture header and picture data elements. The picture dataelement includes a plurality of slice layer data elements. The slicelayer data element comprises a slice header and a plurality of MB layerdata elements. The MB layer data element comprises MB attributeinformation and block layer data elements. Block layer data elementcontains coefficient information. The coefficient information includes amatrix of coefficients.

The separating storage means 120 is adapted to selectively input andstore the transcoded MPEG-2 bit stream through the interface out1, andthe differential bit stream through the interface out2. In the bitstream separating apparatus 1100, the separating storage means 120 mayinput and store the original MPEG-2 bit stream through the inputtingmeans a1.

The first transmission means 141 is adapted to selectively transmit abase bit stream, which will be described later, to a bit stream mergingapparatus 1200 through the outputting interface OUT1.

The request signal receiving means 142 is adapted to receive a requestsignal indicative of a requested bit stream, which will be describedlater.

The second transmission means 143 is adapted to transmit the requestedbit stream, which will be described later, through the outputtinginterface OUT2.

The bit stream extracting means 130 is adapted to extract the requestedbit stream from among bit streams stored in the separating storage means120 in response to the request signal.

The bit stream separating apparatus 1100 thus constructed is adapted toinput an original MPEG-2 bit stream through the inputting terminal a1 toseparate into and output a transcoded MPEG-2 bit stream and adifferential bit stream through the outputting interfaces OUTI and OUT2.

I-B Bit Stream Merging Apparatus 1200

Referring then to FIG. 4 of the drawings, there is shown a preferredembodiment of a bit stream merging apparatus 1200. As shown in FIG. 4,the bit stream merging apparatus 1200 comprises inputting interfacesIN1, IN2, first receiving means 211, merging storage means 220, requestsignal determining means 230, request signal transmission means 213,second receiving means 212, merging bit stream extracting means 241,merging means 242, and an outputting terminal b1. The first receivingmeans 211, the second receiving means 212, and the request signaltransmission means 213 collectively constitute the communication means210. The merging bit stream extracting means 241 and the merging means242 collectively constitute the merging means 240. The bit streammerging apparatus 1200 constitutes the coded signal merging apparatusaccording to the present invention. The merging bit stream extractingmeans 241 constitutes merging coded signal extracting means according tothe present invention.

The first receiving means 211 is adapted to receive the base bit streamtransmitted by the first transmission means 141 of the bit streamseparating apparatus 1100 through the inputting interface IN1. Here, thebase bit stream is intended to mean any one of the original MPEG-2 bitstream, the transcoded MPEG-2 bit stream, and the differential bitstream transmitted by the first transmission means 141.

The merging storage means 220 is adapted to input and store the base bitstream received by the first receiving means 211.

The request signal determining means 230 is adapted to determine arequest signal for a requested bit stream on the basis of the base bitstream stored by the merging storage means 220. More specifically, therequest signal determining means 230 is adapted to determine a requestedbit stream, which is to be merged with the base bit stream toreconstruct the original MPEG-2 bit stream, on the basis of the base bitstream stored by the merging storage means 220 and then determine arequest signal.

The request signal transmission means 213 is adapted to transmit therequest signal for the requested bit stream determined by the requestsignal determining means 230 to the bit stream separating apparatus1100.

The second receiving means 212 is adapted to receive the requested bitstream transmitted by the second transmission means 143 of the bitstream separating apparatus 1100 through the inputting interface IN2.

The merging bit stream extracting means 241 is adapted to extract thebase bit stream from among bit streams stored in the merging storagemeans 220.

The merging means 242 is adapted to merge the base bit stream extractedby the merging bit stream extracting means 241 with the requested bitstream received by the second receiving means 212 on the basis of thesecond coefficient information obtained from the series of secondpicture information of the transcoded MPEG-2 bit stream, and thedifferential coefficient information obtained from the differential bitstream to reconstruct the original MPEG-2 bit stream.

The outputting terminal b1 is adapted to input the reconstructedoriginal MPEG-2 bit stream from the merging means 242 to be outputtedtherethrough.

The bit stream merging apparatus 1200 thus constructed can input atranscoded MPEG-2 bit stream and a differential bit stream through theinputting interfaces IN1 and IN2 to reconstruct and output the originalMPEG-2 bit stream through the outputting terminal b1.

Renderings of an environment in which a preferred embodiment of bitstream separating and merging system 1000 comprising the bit streamseparating apparatus 1100 and the bit stream merging apparatus 1200 isutilized are shown in FIG. 5.

As best shown in FIG. 5, there are provided the bit stream separatingapparatus 1100 according to the present invention, the bit streammerging apparatus 1200 according to the present invention, an encoder60, and transmitting paths.

The encoder 60 is adapted to input original moving picture sequenceinformation, i.e., high-quality moving picture sequence information tooutput high-quality MPEG-2 bit streams, i.e., original MPEG-2 bitstreams. The bit stream separating apparatus 1100 is adapted to inputthe original MPEG-2 bit streams from the encoder 60, and transcode andseparate the original MPEG-2 bit streams to generate transcoded MPEG-2bit streams and differential bit streams. The differential bit streamsare differences between the original MPEG-2 bit streams and thetranscoded MPEG-2 bit streams. The transcoded MPEG-2 bit streams anddifferential bit streams thus generated are transmitted through thetransmitting paths to users.

A user may operate a conventional decoder, not shown, to decode thetranscoded MPEG-2 bit streams to reproduce low-quality moving picturesequence information as shown in FIG. 5.

A user, on the other hand, can operate the bit stream merging apparatus1200 according to present invention to merge the transcoded MPEG-2 bitstreams and the differential bit streams to reconstruct the originalMPEG-2 bit streams, i.e., high-quality MPEG-2 bit streams, therebyenabling to reproduce the original, high-quality moving picture sequenceinformation. The differential bit streams may be transmittedsimultaneously with the transcoded MPEG-2 bit streams or may betransmitted after the transcoded MPEG-2 bit streams are transmitted.

Conventionally, it is required to transmit the original MPEG-2 bitstreams in addition to the transcoded MPEG-2 bit stream through thetransmitting path for reproducing the original, high-quality movingpicture sequence information.

The bit stream separating apparatus 1100 according to the presentinvention, on the other hand, enables to transcode and separate theoriginal MPEG-2 bit stream to generate the differential bit stream inaddition to the transcoded MPEG-2 bit stream. The bit stream mergingapparatus 1200 according to the present invention enables to reproducethe original, high-quality moving picture sequence information from thetranscoded MPEG-2 bit stream and the differential bit stream.

The bit stream merging apparatus 1200 makes it possible to reconstructthe original MPEG-2 bit stream to reproduce the high quality movingpicture sequence information, for instance, from the transcoded MPEG-2bit stream earlier received and stored and the differential bit streamlater received, thereby eliminating the time and effort to transmit theoriginal MPEG-2 bit stream in addition to the transcoded MPEG-2 bitstream through the transmitting path. This leads to the fact that thebit stream separating apparatus 1100 and the bit stream mergingapparatus 1200 according to the present invention make it possible toeffectively utilize the transcoded MPEG-2 bit streams and thetransmitting paths.

Alternatively, the bit stream merging apparatus 1200 may furthercomprises original bit stream storage means, not shown, which is adaptedto input and store the reconstructed original MPEG-2 bit streamreconstructed by the merging means 242. The original bit stream storagemeans of the bit stream merging apparatus 1200 according to the presentinvention enables a user to store the reconstructed original MPEG-2 bitstream, thereby eliminating the time and effort to send the originalMPEG-2 bit stream or resend the transcoded MPEG-2 bit stream or thedifferential bit stream. The original bit stream storage meansconstitute the reconstructed first coded signal storage means accordingto the present invention.

I-C Operation of Bit Stream Separating and Merging System 1000

Referring to FIG. 1 of the drawings, there is shown a first preferredembodiment of a bit stream separating and merging system 1000 accordingto the present invention.

The first preferred embodiment of the bit stream separating and mergingsystem 1000 according to the present invention is shown in FIG. 1 ascomprising a bit stream separating apparatus 1100 for inputting anoriginal MPEG-2 bit stream to separate into a transcoded MPEG-2 bitstream and a differential bit stream, and a bit stream merging apparatus1200 for inputting the transcoded MPEG-2 bit stream and the differentialbit stream.

The constructions of the bit stream separating apparatus 1100 and thebit stream merging apparatus 2100 have already been mentioned.

The operation of the bit stream separating and merging system 1000 willbe described hereinlater in reference to FIG. 1, FIG. 2, and FIG. 4.

In the bit stream separating apparatus 1100, the inputting means a1 isoperated to input the original MPEG-2 bit stream therethrough.

The bit stream converting means 111 of the separating means 110 isoperated to convert the original MPEG-2 bit stream inputted through theinputting means a1 to generate the transcoded MPEG-2 bit stream.

The differential bit stream generating means 112 is operated to inputthe original MPEG-2 bit stream and the transcoded MPEG-2 bit stream fromthe bit stream converting means 111 to generate a differential bitstream on the basis of the first coefficient information obtained fromthe series of first picture information of the original MPEG-2 bitstream, and the second coefficient information obtained from the seriesof the second picture information of the transcoded MPEG-2 bit stream.

The separating storage means 120 is operated to selectively store theoriginal MPEG-2 bit stream inputted through the inputting means a1, thetranscoded MPEG-2 bit stream generated by the bit stream convertingmeans 111, and the differential bit stream generated by differential bitstream generating means 110.

The first transmission means 141 is operated to transmit a base bitstream to the bit stream merging apparatus 1200. Here, the base bitstream is intended to mean any one of the original MPEG-2 bit stream,the transcoded MPEG-2 bit stream, and the differential bit stream.

In the bit stream merging apparatus 1200, the first receiving means 211is operated to receive the base bit stream transmitted by the firsttransmission means 141 of the bit stream separating apparatus 1100.

The merging storage means 220 is operated to store the base bit streamreceived by the first receiving means 211.

The request signal determining means 230 is operated to determine arequest signal for a requested bit stream on the basis of the base bitstream stored by the merging storage means 220.

The request signal transmission means 213 is operated to transmit therequest signal for the requested bit stream determined by the requestsignal determining means 230 to the bit stream separating apparatus1100.

In the bit stream separating apparatus 1100, the request signalreceiving means 142 is operated to receive the request signaltransmitted by the request signal transmission means 213 of the bitstream merging apparatus 1200.

The separating bit stream extracting means 130 is operated to extractthe requested bit stream from among bit streams stored in the separatingstorage means 120 in response to the request signal.

The second transmission means 143 is operated to transmit the requestedbit stream extracted by the separating bit stream extracting means 130to the bit stream merging apparatus 1200.

In the bit stream merging apparatus 1200, the second receiving means 212is operated to receive the requested bit stream transmitted by thesecond transmission means 143 of the bit stream separating apparatus1100.

The merging bit stream extracting means 241 is operated to extract thebase bit stream from among bit streams stored in the merging storagemeans 220.

The merging means 242 is operated to merge the base bit stream extractedby the merging bit stream extracting means 241 with the requested bitstream received by the second receiving means 212 on the basis of thesecond coefficient information obtained from the series of secondpicture information of the transcoded MPEG-2 bit stream, and thedifferential coefficient information obtained from the differential bitstream to reconstruct the original MPEG-2 bit stream.

The outputting means b1 is operated to input the reconstructed originalMPEG-2 bit stream from the merging means 242 to be outputtedtherethrough.

The first embodiment of the bit stream separating and merging system1000 thus constructed makes it possible for a user to receive atranscoded MPEG-2 bit stream at a bit rate lower than that of anoriginal MPEG-2 bit stream to decode, reproduce, and preview low-qualitypicture information, and later receive a differential bit stream to bemerged with the transcoded MPEG-2 bit stream earlier received toreproduce high-quality picture information, thereby eliminating the timeand effort to transmit the original MPEG-2 bit stream, and thuseffectively utilize the transcoded MPEG-2 bit streams and thetransmitting paths.

Furthermore, in the bit stream separating and merging system 1000according to the present invention, the bit stream separating apparatus1100 can firstly transmit the differential bit stream and later transmitthe transcoded MPEG-2 bit stream, and the bit stream merging apparatus1200 can firstly receive the differential bit stream and later receivethe transcoded MPEG-2 bit stream.

II. Second Embodiment of Bit Stream Separating and Merging System 2000

Referring to FIG. 6 of the drawings, there is shown a second preferredembodiment of a bit stream separating and merging system 2000 accordingto the present invention.

The second preferred embodiment of the bit stream separating and mergingsystem 2000 according to the present invention is shown in FIG. 6 ascomprising a bit stream separating apparatus 2100 for inputting anoriginal MPEG-2 bit stream to separate into a transcoded MPEG-2 bitstream and a differential bit stream, and a bit stream merging apparatus2200 for inputting the transcoded MPEG-2 bit stream and the differentialbit stream to reconstruct the original MPEG-2 bit stream.

The bit stream separating apparatus 2100 and the bit stream mergingapparatus 2200 are similar in construction as the bit stream separatingapparatus 1100 and the bit stream merging apparatus 1200 except for thefact that the bit stream separating apparatus 2100 is adapted to storethe differential bit stream in the separating storage means 120 andtransmit the transcoded MPEG-2 bit stream to the bit stream mergingapparatus 2200, and the bit stream merging apparatus 2200 is adapted tofirstly receive the transcoded MPEG-2 bit stream and later receive thedifferential bit stream.

The operation of the bit stream separating and merging system 2000 willbe described with reference to FIG. 6 hereinlater. The sameconstitutional elements are simply represented by the same referencenumerals as those of the bit stream separating apparatus 1100 and thebit stream merging apparatus 1200, and will be thus omitted fromdescription for avoiding tedious repetition.

In the bit stream separating apparatus 2100, the inputting means a1 isoperated to input an original MPEG-2 bit stream 11 therethrough to beoutputted to the bit stream converting means 111.

The bit stream converting means 111 is operated to convert the originalMPEG-2 bit stream 11 inputted through the inputting means a1 to generatethe transcoded MPEG-2 bit stream 12 to be outputted to the differentialbit stream generating means 112 and the first transmission means 141through the interface out1. The bit stream converting means 111 is alsooperated to output the original MPEG-2 bit stream 11 inputted throughthe inputting means a1 to the differential bit stream generating means112.

The differential bit stream generating means 112 is operated to inputthe original MPEG-2 bit stream 11 and the transcoded MPEG-2 bit stream12 from the bit stream converting means 111 to generate a differentialbit stream 13 to be outputted to the separating storage means 120through the interface out2.

The separating storage means 120 is operated to store the differentialbit stream 13 generated by the differential bit stream generating means112.

The first transmission means 141 is operated to transmit the transcodedMPEG-2 bit stream 12 generated by the bit stream converting means 111 tothe bit stream merging apparatus 2200.

In the bit stream merging apparatus 2200, the first receiving means 211is operated to receive the transcoded MPEG-2 bit stream 12 transmittedby the first transmission means 141.

The merging storage means 220 is operated to store the transcoded MPEG-2bit stream 12 received by the first receiving means 211.

The request signal determining means 230 is operated to determine arequest signal 15 for a requested differential bit stream 16 on thebasis of the transcoded MPEG-2 bit stream 12 stored by the mergingstorage means 220. This means that the request signal determining means230 is operated determine a requested differential bit stream 16 and arequest signal 15 for the requested differential bit stream 16 on thebasis of the transcoded MPEG-2 bit stream 12 stored by the mergingstorage means 220.

The request signal transmission means 213 is operated to transmit therequest signal 15 for the requested differential bit stream 16determined by the request signal determining means 230.

In the bit stream separating apparatus 2100, the request signalreceiving means 142 is operated to receive the request signal 15 for therequested differential bit stream 16 transmitted by the request signaltransmission means 213 of the bit stream merging apparatus 2200.

The bit stream extracting means 130 is operated to extract the requesteddifferential bit stream 16 from among bit streams stored in theseparating storage means 120 in response to the request signal.

The second transmission means 143 is operated to transmit the requesteddifferential bit stream 16 extracted by the bit stream extracting means130 from among bit streams stored in the separating storage means 120 tothe bit stream merging apparatus 2200,

In the bit stream merging apparatus 2200, the second receiving means 212is operated to receive the requested differential bit stream 16transmitted by the second transmission means 143 of the bit streamseparating apparatus 2100.

The merging bit stream extracting means 241 is operated to extract thetranscoded MPEG-2 bit stream 14 from among bit streams stored in themerging storage means 220.

The merging means 242 is operated to merge the transcoded MPEG-2 bitstream 14 extracted by the merging bit stream extracting means 241 withthe requested differential bit stream 16 received by the secondreceiving means 212 to reconstruct the original MPEG-2 bit stream 17.

The outputting means b1 is operated to input the reconstructed originalMPEG-2 bit stream 17 from the merging means 242 to be outputtedtherethrough.

According to the present invention, the bit stream merging apparatus2200 may further comprise a decoding means 225 for decoding thetranscoded MPEG-2 bit stream 12 received by the first receiving means211.

The second embodiment of the bit stream separating and merging system1000 thus constructed makes it possible for a user to receive atranscoded MPEG-2 bit stream at a bit rate lower than that of anoriginal MPEG-2 bit stream to decode, reproduce, and preview low-qualitypicture information, and later receive a differential bit stream to bemerged with the transcoded MPEG-2 bit stream earlier received toreproduce high-quality picture information, thereby effectively utilizethe transcoded MPEG-2 bit streams and the transmitting paths.

The bit stream merging apparatus 2200 according to the presentinvention, may comprise original bit stream storage means, not shown,for inputting and storing the reconstructed original MPEG-2 bit stream17 reconstructed by the merging means 242. Alternatively, the mergingstorage means 220 of the bit stream merging apparatus 2200 according tothe present invention may input and store the reconstructed originalMPEG-2 bit stream reconstructed by the merging means 242. The bit streammerging apparatus 2200 thus constructed enables to store thereconstructed original MPEG-2 bit stream once reconstructed, therebyeliminating the time and effort to resend the transcoded MPEG-2 bitstream or the differential bit stream. The original bit stream storagemeans constitute the reconstructed first coded signal storage meansaccording to the present invention.

III. Third Embodiment of Bit Stream Separating and Merging System 3000

Referring to FIG. 7 of the drawings, there is shown a third preferredembodiment of a bit stream separating and merging system 3000 accordingto the present invention.

The third preferred embodiment of the bit stream separating and mergingsystem 3000 according to the present invention is shown in FIG. 7 ascomprising a bit stream separating apparatus 3100 and a bit streammerging apparatus 3200. The bit stream separating apparatus 3100 and thebit stream merging apparatus 3200 are similar in construction as the bitstream separating apparatus 2100 and the bit stream merging apparatus2200 except for the fact that the bit stream merging apparatus 3200further comprises editing means 235 in addition to the request signaldetermining means 230.

The editing means 235 is adapted to cut and combine component parts ofthe transcoded MPEG-2 bit stream stored by the merging storage means 220to generate an edited MPEG-2 bit stream in a desired size.

Some moving picture information is required to be promptly transmittedbut not required to maintain a high picture quality. News moving pictureinformation, for instance, is required to be instantaneously transmittedto editors. The editors, on the other hand, can review and edit the newsmoving picture information as long as the news moving pictureinformation has a minimum picture quality.

In the third preferred embodiment of the bit stream separating andmerging system 3000 according to the present invention, the bit streamseparating apparatus 3100 is adapted to input an original MPEG-2 bitstream 31 to separate into a transcoded MPEG-2 bit stream 32 and adifferential bit stream 33, and store the differential bit stream 33 inthe separating storage means 120 and transmit the transcoded MPEG-2 bitstream 32 to the bit stream merging apparatus 3200. The bit rate of thetranscoded MPEG-2 bit stream 32 is lower than that of the originalMPEG-2 bit stream 31, thereby making it possible for the bit streamseparating apparatus 3100 to transmit the transcoded MPEG-2 bit stream32 to the bit stream merging apparatus 3200 faster than the originalMPEG-2 bit stream 31.

The bit stream merging apparatus 3200, on the other hand, can edit thetranscoded MPEG-2 bit stream 32 thus received to generate an editedtranscoded MPEG-2 bit stream 32.5 in a desired size. The request signaldetermining means 230 is adapted to determine a requested differentialbit stream 36 to be merged with the edited transcoded MPEG-2 bit stream32.5, and a request signal 35 for the requested differential bit stream36 on the basis of the edited transcoded MPEG-2 bit stream 32.5, andthen transmit the request signal 35 for the requested differential bitstream 36 to the bit stream separating apparatus 3100.

In response to the request signal 35 for the requested differential bitstream 36, the bit stream separating apparatus 3100 is adapted toextract the requested differential bit stream 36 from among the storeddifferential bit stream, and transmit the requested differential bitstream 36 to the bit stream merging apparatus 3200.

Upon receiving the requested differential bit stream 36, the bit streammerging apparatus 3200 is adapted to merge the edited transcoded MPEG-2bit stream 32.5 and the requested differential bit stream 36 toreconstruct the original MPEG-2 bit stream 37 in the desired size.

The bit stream separating and merging system 3000 makes it possible fora user to firstly receive and edit the transcoded MPEG-2 bit stream 32and then later receive the differential bit stream 36 corresponding tothe edited MPEG-2 bit stream 32.5 to reconstruct the original MPEG-b bitstream 37 used to reproduce high-quality moving picture information inthe edited size.

The bit stream separating apparatus 3100 is not required to transmit allof the differential bit stream but requested parts of the differentialbit stream only, thereby reducing the volume of the differential bitstream to be transmitted.

The operation of the bit stream separating and merging system 3000 willbe described with reference to FIG. 7 hereinlater. The same operation asthat of the bit stream separating and merging system 2000 will beomitted for avoiding tedious repetition.

The editing means 235 is operated to cut and combine component parts ofthe transcoded MPEG-2 bit stream 32 stored by the merging storage means220 to generate an edited transcoded MPEG-2 bit stream 32.5 in a desiredsize.

The request signal determining means 230 is operated to determine arequest signal 35 for a requested differential bit stream 36 on thebasis of the edited transcoded MPEG-2 bit stream 32.5 generated by theediting means 235. This means that the request signal determining means230 is operated to determine a requested differential bit stream 36 anda request signal 35 for the requested differential bit stream 36 on thebasis of the edited transcoded MPEG-2 bit stream 32.5 generated by theediting means 235.

The request signal transmission means 213 is operated to transmit therequest signal 35 for the requested differential bit stream 36determined by the request signal determining means 230 to the bit streamseparating apparatus 3100.

In the bit stream separating apparatus 3100, the separating bit streamextracting means 130 is operative to extract the requested differentialbit stream 36 from among bit streams stored in the separating storagemeans 120 in response to the request signal 35.

The merging bit stream extracting means 241 is operated to extract theedited transcoded MPEG-2 bit stream 34 from among bit streams stored inthe merging storage means 220.

The merging means 242 is operated to merge the edited transcoded MPEG-2bit stream 34 extracted by the bit stream extracting means 241 with therequested differential bit stream 36 received by the second receivingmeans 212 to reconstruct the original MPEG-2 bit stream 37 in thedesired size.

The third embodiment of the bit stream separating and merging system3000 thus constructed makes it possible for a user to firstly receiveand edit a transcoded MPEG-2 bit stream and then later receive adifferential bit stream corresponding to the MPEG-2 bit stream thusedited to reconstruct an original MPEG-2 bit stream and reproducehigh-quality moving picture information in an edited size, therebyenabling to promptly edit the original MPEG-2 bit stream and reduce thevolume of the differential bit stream to be transmitted.

IV. Fourth Embodiment of Bit Stream Separating and Merging System 4000

Referring to FIG. 8 of the drawings, there is shown a fourth preferredembodiment of a bit stream separating and merging system 4000 accordingto the present invention.

The fourth preferred embodiment of the bit stream separating and mergingsystem 4000 according to the present invention is shown in FIG. 8 ascomprising a bit stream separating apparatus 4100 and a bit streammerging apparatus 4200.

The bit stream separating apparatus 4100 and the bit stream mergingapparatus 4200 are similar in construction as the bit stream separatingapparatus 1100 and the bit stream merging apparatus 1200 except for thefact that the bit stream separating apparatus 4100 is adapted to storethe transcoded MPEG-2 bit stream in the separating storage means 120 andtransmit the differential bit stream to the bit stream merging apparatus2200, and the bit stream merging apparatus 4200 is adapted to firstlyreceive the differential MPEG-2 bit stream and later receive thetranscoded MPEG-2 bit stream.

In the second embodiment of the bit stream separating and merging system2000, the bit stream separating apparatus 2100 is adapted to firstlytransmit the transcoded MPEG-2 bit streams to the bit stream mergingapparatus 2200 and later transmit the differential bit streams to thebit stream merging apparatus 2200 in response to the request signaltransmitted by the bit stream merging apparatus 2200.

In the embodiment of the bit stream separating and merging system 4000according to the present invention, the bit stream separating apparatus4100, on the other hand, is adapted to firstly transmit the differentialbit streams to the bit stream merging apparatus 4200 and later transmitthe transcoded MPEG-2 bit streams in response to the request signaltransmitted by the bit stream merging apparatus 4200.

A program provider, i.e., a broadcast station, for instance, can deliverdifferential bit streams to a plurality of subscribers in their homes.The differential bit streams delivered are automatically stored in homeservers or local storages in respective homes.

When a subscriber wants to watch a specific film program, the subscribercan transmit a request signal for a requested transcoded MPEG-2 bitstream to be merged with the differential bit stream earlier deliveredcontaining the film program to be watched, to the broadcast station. Inresponse to the request signal, the broadcast station can transmit therequested transcoded MPEG-2 bit stream to the subscriber and thesubscriber can watch the program by merging the requested transcodedMPEG-2 bit stream just received and the differential bit stream alreadystored. The subscriber can receive the transcoded MPEG-2 bit streamfaster than the original MPEG-2 bit stream since the bit rate of thetranscoded MPEG-2 bit stream is lower than that of the original MPEG-2bit stream. This means that the bit stream separating and merging system4000 can promptly deliver the moving picture information to subscribers.

Furthermore, the differential bit stream earlier delivered tosubscribers cannot be decoded, thereby preventing the illegal copy ofthe moving picture information.

The operation of the bit stream separating and merging system 4000 willbe described with reference to FIG. 8 hereinlater. The same operation asthat of the bit stream separating and merging system 1000 will beomitted.

In the bit stream separating apparatus 4100, the inputting means al isoperated to input an original MPEG-2 bit stream 41 therethrough to beoutputted to the bit stream converting means 111.

The bit stream converting means 111 is operated to convert the originalMPEG-2 bit stream 41 inputted through the inputting means a1 to generatethe transcoded MPEG-2 bit stream 43 to be outputted to the differentialbit stream generating means 112 and the separating storage means 120through the interface out1. The bit stream converting means 111 is alsooperated to output the original MPEG-2 bit stream 41 inputted throughthe inputting means a1 to the differential bit stream generating means112.

The differential bit stream generating means 112 is operated to inputthe original MPEG-2 bit stream 41 and the transcoded MPEG-2 bit stream43 from the bit stream converting means 111 to generate a differentialbit stream 42 to be outputted to the first transmission means 141through the interface out2.

The separating storage means 120 is operated to input and store thetranscoded MPEG-2 bit stream 43 generated by the bit stream convertingmeans 111.

The first transmission means 141 is operated to input and transmit thedifferential bit stream 42 generated by the differential bit streamgenerating means 112 to the bit stream merging apparatus 4200.

In the bit stream merging apparatus 4200, the first receiving means 211is operated to receive the differential bit stream 42 transmitted by thefirst transmission means 141.

The merging storage means 220 is operated to store the differential bitstream 42 received by the first receiving means 211.

The request signal determining means 230 is operated to determine arequested transcoded MPEG-2 bit stream 45 and a request signal 44 forthe requested transcoded MPEG-2 bit stream 45 on the basis of thedifferential bit stream 42 stored by the merging storage means 220.

The request signal transmission means 213 is operated to transmit therequest signal 44 for the requested transcoded MPEG-2 bit stream 45determined by the request signal determining means 230.

In the bit stream separating apparatus 4100, the request signalreceiving 142 is operated to receive the request signal 44 transmittedby the request signal transmission means 213.

The separating bit stream extracting means 130 is operated to extractthe requested transcoded MPEG-2 bit stream 45 from among bit streamsstored in the separating storage means 120 in response to the requestsignal 44.

The second transmission means 143 is operated to transmit the requestedtranscoded MPEG-2 bit stream 45 extracted by the separating bit streamextracting means 130 to the bit stream merging apparatus 4200.

In the bit stream merging apparatus 4200, the second receiving means 212is operated to receive the requested transcoded MPEG-2 bit stream 45transmitted by the second transmission means 143 of the bit streamseparating apparatus 4100.

The merging bit stream extracting means 241 is operated to extract thedifferential bit stream 46 stored by the merging storage means 220.

The merging means 242 is operated to merge the differential bit stream46 extracted by the merging bit stream extracting means 241 with thetranscoded MPEG-2 bit stream 45 received by the second receiving means212 to reconstruct the original MPEG-2 bit stream 47.

According to the present invention, the first transmission means 141 ofthe bit stream separating apparatus 4100 and the first receiving means211 of the bit stream merging apparatus 4200 may transmit and receivebit streams by way of broadcasting.

The fourth embodiment of the bit stream separating and merging system4000 thus constructed enables to firstly deliver the differential bitstream to a user in their homes and later transmit the transcoded MPEG-2bit stream to the user in response to the request signal, therebypromptly delivering moving picture information and preventing theillegal copy of the moving picture information.

V. Fifth Embodiment of Bit Stream Separating and Merging System 5000

Referring FIG. 9 of the drawings, there is shown a fifth preferredembodiment of a bit stream separating and merging system 5000 accordingto the present invention. The same constitutional elements are simplyrepresented by the same reference numerals as those of the bit streamseparating apparatus 1100 and the bit stream merging apparatus 1200, andwill be thus omitted from description for avoiding tedious repetition.

The fifth preferred embodiment of the bit stream separating and mergingsystem 5000 according to the present invention is shown in FIG. 9 ascomprising a bit stream separating means 5100 and a bit stream mergingapparatus 5200.

The bit stream merging apparatus 5200 further comprises a decoding means280 for decoding MPEG-2 bit streams and merging bit stream convertingmeans 271 for transcoding the original MPEG-2 bit stream to generate atranscoded MPEG-2 bit stream. The merging bit stream converting means271 constitutes bit stream converting means according to the presentinvention.

In the fifth embodiment of the bit stream separating and merging system5000 according to the present invention, the bit stream separatingapparatus 5100 is adapted to transmit the original MPEG-2 bit stream tothe bit stream merging apparatus 5200.

The bit stream merging apparatus 5200 thus constructed is adapted todecode and reproduce high quality moving picture information from theoriginal MPEG-2 bit stream 51 transmitted by the bit stream separatingapparatus 5100, and transcode the original MPEG-2 bit stream 51 togenerate the transcoded MPEG-2 bit stream 53 to be stored in the mergingstorage means 220. The bit stream separating apparatus 5100 is adaptedto store the differential bit stream 52 in the separating storage means120.

The bit stream separating and merging system 5000 thus constructed doesnot need to store the original MPEG-2 bit stream 51, which has a largebit rate in comparison with bit rates of the transcoded MPEG-2 bitstream 53 and the differential bit stream 52, thereby enabling to savethe storage capacity of the bit stream separating apparatus 5100 and thebit stream merging apparatus 5200.

The operation of the bit stream separating and merging system 5000 willbe described with reference to FIG. 9 hereinlater. The same operation asthat of the bit stream separating and merging system 1000 will beomitted.

In the bit stream separating apparatus 5100, the inputting means a1 isoperated to input an original MPEG-2 bit stream 51 therethrough to beoutputted to the bit stream converting means 111 and the firsttransmission means 141.

The bit stream converting means 111 is operated to convert the originalMPEG-2 bit stream 51 inputted through the inputting means a1 to generatethe transcoded MPEG-2 bit stream to be outputted to the differential bitstream generating means 112. The bit stream converting means 111 is alsooperated to output the original MPEG-2 bit stream 51 inputted throughthe inputting means a1 to the differential bit stream generating means112.

The differential bit stream generating means 112 is operated to inputthe original MPEG-2 bit stream 51 and the transcoded MPEG-2 bit streamfrom the bit stream converting means 111 to generate a differential bitstream 52 to be outputted to the separating storage means 120 throughthe interface out2.

The separating storage means 120 is operated to input and store thedifferential bit stream 52 generated by the differential bit streamgenerating means 112.

The first transmission means 141 is operated to input and transmit theoriginal MPEG-2 bit stream 51 inputted through the inputting means a1 tothe bit stream merging apparatus 5200.

In the bit stream merging apparatus 5200, the first receiving means 211is adapted to receive the original MPEG-2 bit stream 51 transmitted bythe first transmission means 141 of the bit stream separating apparatus5100.

The decoding means 280 is operated to input and decode the originalMPEG-2 bit stream 51 received by the first receiving means 211.

The merging bit stream converting means 271 is operated to input theoriginal MPEG-2 bit stream 51 received by the first receiving means 211to generate a transcoded MPEG-2 bit stream 53.

The merging storage means 220 is operated to input and store thetranscoded MPEG-2 bit stream 53 generated by the merging bit streamconverting means 271.

The request signal determining means 230 is operated to determine arequested differential bit stream 55 and a request signal 54 for therequested differential bit stream 55 on the basis of the transcodedMPEG-2 bit stream 53 stored by the merging storage means 220.

The request signal transmission means 213 is operated to transmit therequest signal 54 for the requested differential bit stream 55determined by the request signal determining means 230 to the bit streamseparating apparatus 5100.

In the bit stream separating apparatus 5100, the request signalreceiving means 142 is operated to receive the request signal 54transmitted by the request signal transmission means 213 of the bitstream merging apparatus 5200.

The separating bit stream extracting means 130 is operated to extractthe requested differential bit stream 55 from among bit streams storedin the separating storage means 120 in response to the request signal54.

The second transmission means 143 is operated to transmit the requesteddifferential bit stream 55 extracted by the separating bit streamextracting means 130 to the bit stream merging apparatus 5200.

In the bit stream merging apparatus 5200, the second receiving means 212is operated to receive the requested differential bit stream 55transmitted by the second transmission means 143 of the bit streamseparating apparatus 5100.

The merging bit stream extracting means 241 is operated to extract thetranscoded MPEG-2 bit stream 56 from among bit streams stored in themerging storage means 220.

The merging means 242 is operated to merge the transcoded MPEG-2 bitstream 56 extracted by the merging bit stream extracting means 241 withthe requested differential bit stream 55 received by the secondreceiving means 212 to reconstruct the original MPEG-2 bit stream 57 inthe desired size.

The bit stream separating and merging system 5000 thus constructed doesnot need to store the original MPEG-2 bit stream, which has a large bitrate in comparison with bit rates of the transcoded MPEG-2 bit streamand the differential bit stream, thereby enabling to save the storagecapacity of the bit stream separating apparatus 5100 and the bit streammerging apparatus 5200.

VI. Sixth Embodiment of Bit Stream Separating and Merging System 6000

Referring to FIG. 10 of the drawings, there is shown a sixth preferredembodiment of a bit stream separating and merging system 6000 accordingto the present invention.

The sixth preferred embodiment of the bit stream separating and mergingsystem 6000 according to the present invention is shown in FIG. 10 ascomprising a bit stream separating apparatus 6100 and a bit streammerging apparatus 6200. The same constitutional elements are simplyrepresented by the same reference numerals as those of the bit streamseparating apparatus 1100 and the bit stream merging apparatus 1200, andwill be thus omitted from description.

The construction of the sixth embodiment of the bit stream separatingand merging system 6000 is similar to that of the fourth embodiment ofthe bit stream separating and merging system 4000 except for the factsthat the bit stream separating apparatus 6100 is adapted to transmit thetranscoded MPEG-2 bit stream 61 and the bit stream merging apparatus6200 is adapted to receive the original MPEG-2 bit stream 61 to generatea differential bit stream 63 and store the differential bit stream 63thus generated.

The bit stream merging apparatus 6200 further comprises decoding means280 and merging separating means 270. The decoding means 280 is adaptedto decode a MPEG-2 bit stream. The merging separating means 270 isadapted to input the original MPEG-2 bit stream 61 to generate adifferential bit stream 64. The merging separating means 270 constitutesmerging differential coded signal generating means according to thepresent invention.

More specifically, the merging separating means 270 includes bit streamconverting means 271 and differential bit stream generating means 272 asshown in FIG. 10. The bit stream converting means 271 is adapted toinput the original MPEG-2 bit stream 60 to generate a transcoded MPEG-2bit stream. The bit stream converting means 271 is adapted to output theoriginal MPEG-2 bit stream 61 and the transcoded MPEG-2 bit stream thusgenerated to the differential bit stream generating means 272. Thedifferential bit stream generating means 272 is adapted to input theoriginal MPEG-2 bit stream 61 and the transcoded MPEG-2 bit stream fromthe bit stream converting means 271 to generate a differential bitstream 64.

The bit stream separating and merging system 6000 thus constructed doesnot need to store the original MPEG-2 bit stream, which has a large bitrate in comparison with bit rates of the transcoded MPEG-2 bit streamand the differential bit stream, thereby enabling to save the storagecapacity of the bit stream separating apparatus 6100 and the bit streammerging apparatus 6200.

The operation of the bit stream separating and merging system 6000 willbe described with reference to FIG. 10 hereinlater. The same operationdescribed hereinearlier will be omitted.

In the bit stream separating apparatus 6100, the inputting means al isoperated to input an original MPEG-2 bit stream 61 therethrough to beoutputted to the bit stream converting means 111 and the firsttransmission means 141.

The bit stream converting means 111 is operated to convert the originalMPEG-2 bit stream 61 inputted through the inputting means a1 to generatea transcoded MPEG-2 bit stream 62 to be outputted to the merging storagemeans 120 through the interface out1.

The separating storage means 120 is operated to input and store thetranscoded MPEG-2 bit stream 62 generated by the bit stream convertingmeans 111.

The first transmission means 141 is operated to transmit the originalMPEG-2 bit stream 61 inputted through inputting means a1 to the bitstream merging apparatus 6200.

In the bit stream merging apparatus 6200, the first receiving means 211is operated to receive the original MPEG-2 bit stream 61 transmitted bythe first transmission means 141 of the bit stream separating apparatus6100.

The decoding means 280 is operated to decode the original MPEG-2 bitstream 61 received by the first receiving means 211.

The merging bit stream converting means 271 is operated to input theoriginal MPEG-2 bit stream 61 received by the first receiving means 211to generate a transcoded MPEG-2 bit stream.

The merging differential bit stream generating means 272 is operated toinput the original MPEG-2 bit stream 61 received by the first receivingmeans 211 and the transcoded MPEG-2 bit stream generated by the mergingbit stream converting means 271 to generate the differential bit stream63.

The merging storage means 220 is operated to store the differential bitstream 63 thus generated by the merging separating means 270.

The request signal determining means 230 is operated to determine arequested transcoded MPEG-2 bit stream 65 and a request signal 64 forthe requested transcoded MPEG-2 bit stream 65 on the basis of thedifferential bit stream 63 stored by the merging storage means 220.

The request signal transmission means 213 is operated to transmit therequest signal 64 for the requested transcoded MPEG-2 bit stream 65determined by the request signal determining means 230 to the bit streamseparating apparatus 6100.

In the bit stream separating apparatus 6100, the request signalreceiving means 142 is operated to receive the request signal 64transmitted by the request signal transmission means 213 of the bitstream merging apparatus 6200.

The separating bit stream extracting means 130 is operated to extractthe requested transcoded MPEG-2 bit stream 65 from among bit streamsstored in the separating storage means 120 in response to the requestsignal 64.

The second transmission means 143 is operated to transmit the requestedtranscoded MPEG-2 bit stream 65 extracted by the separating bit streamextracting means 130 to the bit stream merging apparatus 6200.

In the bit stream merging apparatus 6200, the second receiving means 212is operated to receive the requested transcoded MPEG-2 bit stream 65transmitted by the second transmission means 143 of the bit streamseparating apparatus 6100.

The merging bit stream extracting means 241 is operated to extract thedifferential MPEG-2 bit stream 66 from among bit streams stored in themerging storage means 220.

The merging means 242 is operated to merge the differential bit stream66 extracted by the merging bit stream extracting means 241 with therequested transcoded MPEG-2 bit stream 65 received by the secondreceiving means 212 to reconstruct the original MPEG-2 bit stream 67 inthe desired size.

The bit stream separating and merging system 6000 thus constructed doesnot need to store the original MPEG-2 bit stream, which has a large bitrate in comparison with bit rates of the transcoded MPEG-2 bit streamand the differential bit stream, thereby enabling to save the storagecapacity of the bit stream separating apparatus 6100 and the bit streammerging apparatus 6200.

VII. Seventh Embodiment of Bit Stream Separating and Merging System 7000

Referring to FIG. 11 of the drawings, there is shown a seventh preferredembodiment of a bit stream separating and merging system 7000 accordingto the present invention.

Each of the above described embodiments of the bit stream separating andmerging systems 1000 to 6000 comprises a single bit stream separatingapparatus for inputting an original MPEG-2 bit stream to separate into atranscoded MPEG-2 bit stream and a differential bit stream, and a singlebit stream merging apparatus for inputting a transcoded MPEG-2 bitstream and a differential MPEG-2 bit stream to reconstruct an originalMPEG-2 bit stream.

The seventh preferred embodiment of the bit stream separating andmerging system 7000, on the other hand, as best shown in FIG. 11,comprises a multi-output bit stream separating apparatus 7100 forinputting an original MPEG-2 bit stream to separate into a plurality oftranscoded MPEG-2 bit streams and a plurality of differential bitstreams; and a multi-input bit stream merging apparatus 7200 forinputting a plurality of transcoded MPEG-2 bit streams and a pluralityof differential bit streams to reconstruct the original MPEG-2 bit.According to the present invention, the multi-input bit stream mergingapparatus 7200 can also output a plurality of transcoded MPEG-2 bitstreams.

In the bit stream separating and merging system 7000 thus constructed,the multi-output bit stream separating apparatus 7100 can input, forinstance, an original MPEG-2 bit stream having a large bit rate toseparate into and transmit one or more transcoded MPEG-2 bit streams anda plurality of differential bit streams and the multi-input bit streammerging apparatus 7200 can input and merge the one or more transcodedMPEG-2 bit streams and the differential bit streams thus multiple-timesseparated to reconstruct the original MPEG-2 bit stream of the large bitrate. Alternatively, the multi-input bit stream merging apparatus 7200can reconstruct and output a plurality of transcoded MPEG-2 bit streamin addition to the original MPE-2 bit stream. Each of the transcodedMPEG-2 bit streams and the differential bit streams thus multiple-timesseparated has a small bit rate in comparison with a bit rate of theoriginal MPEG-2 bit stream. The bit stream separating and merging system7000 makes it possible to promptly- and reliably transmit and receive anoriginal MPEG-2 bit stream having a large bit rate by transmitting andreceiving one or more transcoded MPEG-2 bit streams and a plurality ofdifferential bit streams in place of the original MPEG-2 bit stream.

The constructions of the multi-output bit stream separating apparatus7100 and the multi-input bit stream merging unit 7200 will be describedin detail before describing the operation of the bit stream separatingand merging system 7000.

VII-A Multi-Output Bit Stream Separating Apparatus 7100

Referring to FIG. 12 of the drawings, there is shown a multi-output bitstream separating apparatus 7100 for inputting an original MPEG-2 bitstream 71 to separate into one transcoded MPEG-2 bit streams and aplurality of differential bit streams. As shown in FIG. 12, themulti-output bit stream separating apparatus 7100 comprises a plurality(the number m) of bit stream separating units 71001 to 7100 m includinga 1st bit stream separating unit 71001 up to a m-th bit streamseparating unit 7100 m wherein m is an integer not less than two.

Each of the bit stream separating units 71001 to 7100 m is entirely samein construction as that of the bit stream separating apparatus 1100according to the present invention, which has previously been mentioned,and adapted to input a MPEG-2 bit stream to be transcoded, to separateinto a transcoded MPEG-2 bit stream and a differential bit stream, whichis a difference between the transcoded MPEG-2 bit stream and the MPEG-2bit stream. The same constitutional elements are simply represented bythe same reference numerals as those of the bit stream separatingapparatus 1100 and will be thus omitted from description.

The multi-output bit stream separating apparatus 7100 will be describedin reference to FIG. 12, hereinlater.

The 1st bit stream separating unit 71001 is adapted to input theoriginal MPEG-2 bit stream 71 having a bit rate of 10 Mbps to separateinto a 1st transcoded MPEG-2 bit stream 72.1 having a bit rate of 8 Mbpsand a 1st differential bit stream 73.1 having a bit rate of 2 Mbps. The1st differential bit stream 73.1 is a difference between the originalMPEG-2 bit stream 71 and the 1st transcoded MPEG-2 bit stream 72.1. The1st bit stream separating unit 71001 is adapted to output the 1sttranscoded MPEG-2 bit stream 72.1 to the 2nd bit stream separating unit71002.

The 2nd bit stream separating unit 71002 is adapted to input the 1sttranscoded MPEG-2 bit stream 72.1 having a bit rate of 8 Mbps from the1st bit stream separating unit 71001 to separate into a 2nd transcodedMPEG-2 bit stream 72.2 having a bit rate of 6 Mbps and a 2nddifferential bit stream 73.2 having a bit rate of 2 Mbps. The 2nddifferential bit stream 73.2 is a difference between the 1st transcodedMPEG-2 bit stream 72.1 and the 2nd transcoded MPEG-2 bit stream 72.2.The 2nd bit stream separating unit 71002 is adapted to output the 2ndtranscoded MPEG-2 bit stream 72.3 to the 3rd bit stream separating unit71003.

The multi-output bit stream separating apparatus 7100 thus constructedcan transmit the original MPEG-2 bit stream having a bit rate of 10 Mbpsby transmitting one transcoded MPEG-2 bit stream and a plurality ofdifferential bit streams each having a bit rate lower than 10 Mbps.

Any one of the bit stream separating units 71001 to 7100 m ishereinlater referred to as i-th bit stream separating unit 7100 iwherein i is an integer equal to or less than m.

The i-th bit stream separating unit 7100 i is adapted to input an(i−1)-th transcoded MPEG-2 bit stream 72.(i−1) from the (i−1) th bitstream separating unit 7100 i−1 to separate into an i-th transcodedMPEG-2 bit stream 72.i and an i-th differential bit stream 73.i. Thei-th bit stream separating unit 7100 i is adapted to output the i-thtranscoded MPEG-2 bit stream 72.i to the (i+1)-th bit stream separatingunit 7100 i+1. Here, the i-th differential bit stream 73.i is intendedto mean a difference between the (i−1)-th transcoded MPEG-2 bit stream72.(i−1) and the i-th transcoded MPEG-2 bit stream 72.i.

According to the present invention, any one of the bit stream separatingunits 71001 to 7100 m, i.e., an i-th bit stream separating unit 7100 ican transmit i-th transcoded MPEG-2 bit stream 72.1 to an externaldevice such as a decoder. The multi-output bit stream separatingapparatus 7100 thus constructed can input an original MPEG-2 bit streamto output a plurality of transcoded MPEG-2 bit stream and a plurality ofdifferential bit streams.

For better understanding, the multi-output bit stream separatingapparatus 7100 will be described in detail in reference to the i-th bitstream separating unit 7100 i.

The i-th bit stream separating unit 7100 i is similar in construction asthe bit stream separating apparatus 1100 shown in FIG. 2 as comprisingan inputting terminal INi, i-th bit stream converting means 111 i, i-thdifferential bit stream generating means 112 i, i-th separating storagemeans 120 i, i-th first transmission means 141 i, i-th request signalreceiving means 142 i, i-th bit stream extracting means 130 i, i-thsecond transmission means 143 i, and i-th outputting interface OUTi.

The i-th inputting means INi is adapted to input the (i−1)-th transcodedMPEG-2 bit stream 72.(i−1) therethrough from the (i−1)-th bit streamseparating unit 7100 i−1. Here, 0-th transcoded MPEG-2 bit stream is theoriginal MPEG-2 bit stream. 0-th bit stream separating unit is intendedto mean the inputting means a1.

The (i−1)-th transcoded MPEG-2 bit stream 72.(i−1) is generated as aresult of encoding original moving picture sequence signal and consistsof a series of (i−1)-th picture information having (i−1)-th coefficientinformation. The (i−1)-th coefficient information includes a matrix of(i−1)-th coefficients.

The i-th bit stream converting means 111 i is adapted to convert the(i−1)-th transcoded MPEG-2 bit stream 72.(i−1) inputted through the i-thinputting means INI to generate the i-th transcoded MPEG-2 bit stream72.i. The i-th bit stream converting means 111 i is adapted to outputthe i-th transcoded MPEG-2 bit stream 72.i thus generated to the(i+1)-th inputting means INi+1 of the (i+1)-th bit stream separatingunit 7100 i+1 through the interface out1. The i-th bit stream convertingmeans 111 i is also adapted to output the (i−1)-th transcoded MPEG-2 bitstream 72.(i−1) and the i-th transcoded MPEG-2 bit stream 72.i to thei-th differential bit stream generating means 112 i.

The i-th differential bit stream generating means 112 i is adapted toinput the (i−1)-th transcoded MPEG-2 bit stream 72.(i−1) and the i-thtranscoded MPEG-2 bit stream 72.i from the bit stream converting means111 i to generate an i-th differential bit stream 73.i on the basis ofthe (i−1)-th second coefficient information obtained from the series of(i−1)-th second picture information of the (i−1)-th transcoded MPEG-2bit stream 72.(i−1), and the i-th second coefficient informationobtained from the series of the i-th second picture information of thetranscoded MPEG-2 bit stream 72.i. The i-th differential bit stream 73.iis intended to mean a difference between the (i−1)-th transcoded MPEG-2bit stream 72.(i−1) and the i-th transcoded MPEG-2 bit stream 72.i.

The i-th separating storage means 120 i is adapted to selectively storethe (i−1)-th transcoded MPEG-2 bit stream 72.(i−1), the i-th transcodedMPEG-2 bit stream 72.i, and the i-th differential bit stream 73.i.

The i-th first transmission means 141 i is adapted to selectivelytransmit the (i−1)-th transcoded MPEG-2 bit stream, the i-th transcodedMPEG-2 bit stream 72.i, and the i-th differential bit stream 73.i to anexternal device such as, for instance, the i-th bit stream merging unit7200 i of the multi-input bit stream merging apparatus 7200.

The i-th request signal receiving means 142 i is adapted to receive arequest signal indicative of a requested bit stream to be transmitted.The request signal indicative of the requested bit stream is determinedon the basis of a base signal, which is any one of the (i−1)-thtranscoded MPEG-2 bit stream 72.(i−1), the i-th transcoded MPEG-2 bitstream 72.i, or the i-th differential bit stream 73.i.

The i-th separating bit stream extracting means 130 i is adapted toextract the requested bit stream from among bit streams stored in thei-th separating storage means 120 i in response to the request signal.

The i-th second transmission means 143 i is adapted to transmit therequested bit stream extracted by the i-th separating bit streamextracting means 130 i.

VII-B Multi-Input Bit Stream Merging Apparatus 7200

Referring to FIG. 13 of the drawings, there is shown a multi-input bitstream merging apparatus 7200 for inputting one or more transcodedMPEG-2 bit streams and a plurality of differential bit streams toreconstruct an original MPEG-2 bit stream. As shown in FIG. 13, themulti-input bit stream merging apparatus 7200 comprises a plurality (thenumber n) of bit stream merging units 72001 to 7200 n including a 1stbit stream merging unit 72001 up to a n-th bit stream merging unit 7200i wherein n is an integer not less than two.

Each of the bit stream merging units 72001 to 7200 n is entirely same inconstruction as the bit stream merging apparatus 1200 according to thepresent invention, which has previously been mentioned, and adapted toinput a transcoded MPEG-2 bit stream and a differential bit stream toreconstruct a MPEG-2 bit stream before separated into the transcodedMPEG-2 bit stream and the differential bit stream. The sameconstitutional elements are simply represented by the same referencenumerals as those of the bit stream separating apparatus 1100 and willbe thus omitted from description.

The multi-input bit stream merging apparatus 7200 will be described inreference to FIG. 13 hereinlater.

The 2nd bit stream merging unit 72002 is adapted to input the 2ndtranscoded MPEG-2 bit stream 72.2 having a bit rate of 6 Mbps from the3rd bit stream merging unit 72003, and the 2nd differential bit stream73.2 having a bit rate of 2 Mbps from an external device such as, forinstance, the 2nd bit stream separating unit 71002, to reconstruct the1st transcoded MPEG-2 bit stream 72.1 having a bit rate of 8 Mbps. The2nd bit stream merging unit 72002 is adapted to output the 1 sttranscoded MPEG-2 bit stream thus reconstructed to the 1st bit streammerging unit 72001.

The 1st bit stream merging unit 72001 is adapted to input the 1sttranscoded MPEG-2 bit stream 72.1 having a bit rate of 8 Mbps from the2nd bit stream merging unit 72002, and the 1st differential bit stream73.1 having a bit rate of 2 Mbps from an external device such as, forinstance, the 1st bit stream separating unit 71001 to reconstruct theoriginal MPEG-2 bit stream 71 having a bit rate of 10 Mbps.

Any one of the bit stream separating units 81001 to 8100 m ishereinlater referred to as i-th bit stream separating unit 8100 iwherein i is an integer equal to or less than n. This means that thei-th bit stream merging unit 7200 i is adapted to input an i-thtranscoded MPEG-2 bit stream 72.i and an i-th differential bit stream73.i to reconstruct a (i−1)-th transcoded MPEG-2 bit stream wherein i isan integer equal to or less than n.

In this embodiment, the i-th bit stream merging unit 7200 i is adaptedto input the i-th transcoded MPEG-2 bit stream 72.i from the (i+1)-thbit stream merging unit 7200 i+1 and the i-th differential bit stream73.i from an external device such as, for instance, the i-th bit streamseparating unit 7100 i. The i-th bit stream merging unit 7200 i isadapted to output the (i−1)-th transcoded MPEG-2 bit stream thusreconstructed to the (i−1)-th bit stream merging unit 7200 i−1.

The multi-input bit stream merging apparatus 7200 thus constructed canreceive an original MPEG-2 bit stream having a bit rate of, forinstance, 10 Mbps by receiving one single transcoded MPEG-2 bit streamand a plurality of differential bit streams each having a bit rate lowerthan 10 Mbps.

The i-th bit stream merging unit 7200 i can, however, input any one ofthe i-th transcoded MPEG-2 bit stream 72.i and the i-th differential bitstream 73.i from the (i+1)-th bit stream merging unit 7200 i+1 and theother one of them from an external device such as, for instance, thei-th bit stream separating unit 7100 i. Furthermore, the i-th bit streammerging unit 7200 i can output the (i−1)-th transcoded MPEG-2 bit streamthus reconstructed to an external device such as a decoder.

The multi-input bit stream merging apparatus 7200 thus constructed caninput a plurality of transcoded MPEG-2 bit streams and a plurality ofdifferential bit streams to output a plurality of transcoded MPEG-2 bitstreams.

For better understanding, the multi-input bit stream merging apparatus7200 will be described in detail in reference to the i-th bit streammerging unit 7200 i will be described in detail.

The i-th bit stream merging unit 7200 i is similar in construction asthe bit stream separating apparatus 1200 shown in FIG. 4 as comprisinginputting interfaces, i-th first receiving means 211 i, i-thmerging-storage means 220 i, i-th request signal determining means 230i, i-th request signal transmission means 213 i, i-th second receivingmeans 212 i, i-th merging bit stream extracting means 241 i, i-thmerging means 242 i, and outputting means OUTi.

The i-th first receiving means 211 i is adapted to receive a base bitstream. In this embodiment, the base bit stream is an i-th transcodedMPEG-2 bit stream 72.i. This means that the i-th first receiving means211 i is adapted to receive the base bit stream, i.e., the i-thtranscoded MPEG-2 bit stream 72.i from the (i+1)-th bit stream mergingunit 7200 i+1.

The i-th first receiving means 211 i may receive the base bit streamfrom the i-th bit stream separating unit 7100 i, and the base bit streammay be any one of the i-th transcoded MPEG-2 bit stream 72.i, the(i−1)-th transcoded MPEG-2 bit stream 72.(i−1), and the i-thdifferential bit stream 73.i.

The i-th merging storage means 220 i is adapted to store the base bitstream received by the i-th first receiving means 211 i.

The i-th request signal determining means 230 i is adapted to determinea requested bit stream and a request signal for the requested bit streamon the basis of the base bit stream stored by the i-th merging storagemeans 220 i. If the base bit stream is the (i−1)-th transcoded MPEG-2bit stream 72.(i−1), the i-th request signal determining means 230 i isadapted to determine no request signal, and the i-th bit stream mergingunit 7200 i is adapted to output the (i−1)-th transcoded MPEG-2 bitstream 72.(i−1) therethrough. In this embodiment, the base bit stream isthe i-th transcoded MPEG-2 bit stream 72.i, and the i-th request signaldetermining means 230 i is adapted to determine a requested bit stream,i.e., an i-th differential bit stream 73.i, and a request signal for therequested bit stream on the basis of the i-th transcoded MPEG-2 bitstream 72.i stored by the i-th merging storage means 220 i.

The i-th request signal transmission means 213 i is adapted to transmitthe request signal for the requested bit stream determined by the i-threquest signal determining means 230 i to the bit stream separating unit7100 i.

The i-th second receiving means 212 i is adapted to receive therequested bit stream.

The i-th merging bit stream extracting means 241 i is adapted to extractthe base bit stream from among bit streams stored in the i-th mergingstorage means 220 i.

The i-th merging means 242 i is adapted to merge the base bit stream,i.e., the i-th transcoded MPEG-2 bit stream 72.i, extracted by the i-thmerging bit stream extracting means 241 i with the requested bit stream,i.e., i-th differential bit stream 73.i, received by the i-th secondreceiving means 212 i to reconstruct the (i−1)-th transcoded MPEG-2 bitstream 72.(i−1) on the basis of the i-th second coefficient informationobtained from the series of i-th second picture information of the i-thtranscoded MPEG-2 bit stream 72.i, and the i-th differential coefficientinformation obtained from the i-th differential bit stream 73.i.

The i-th outputting means OUTi is adapted to input the reconstructed(i−1)-th transcoded MPEG-2 bit stream from the i-th merging means 242 ito be outputted therethrough to the (i−1)-th bit stream merging unit7200 i−1.

According to the present invention, the i-th outputting means OUTi canoutput the reconstructed (i−1)-th transcoded MPEG-2 bit stream to anexternal device, such as a decoder as well.

As will be seen from the foregoing description, the multi-input bitstream merging apparatus 7200 thus constructed can input one or moretranscoded MPEG-2 bit streams and a plurality of differential bitstreams to one or more MPEG-2 bit streams before transcoded, therebymaking it possible for a user to selectively decode transcoded MPEG-bitstreams to reproduce a moving picture information of a desired picturequality.

VII-C Operation of Bit Stream Separating and Merging System 7000

Referring to FIG. 11 of the drawings, there is shown a seventh preferredembodiment of a bit stream separating and merging system 7000 accordingto the present invention.

The seventh preferred embodiment of the bit stream separating andmerging system 7000 is shown in FIG. 11 as comprising a multi-output bitstream separating apparatus 7100 for inputting an original MPEG-2 bitstream to separate into one or more transcoded MPEG-2 bit streams and aplurality of differential bit streams; and a multi-input bit streammerging apparatus 7200 for inputting one or more transcoded MPEG-2 bitstreams and a plurality of differential bit streams to reconstruct theoriginal MPEG-2 bit stream.

The multi-output bit stream separating apparatus 7100 comprises aplurality (the number m) of bit stream separating units 71001 to 7100 mincluding a 1st bit stream separating unit 71001 up to a m-th bit streamseparating unit 7100 m wherein m is an integer not less than two.

The multi-input bit stream merging apparatus 7200 comprises a plurality(the number n) of the bit stream merging units 72001 to 7200 n includinga 1st bit stream merging unit 72001 up to a n-th bit stream merging unit7200 n wherein n is an integer not less than two. Furthermore, n can beequal to or less than m.

The constructions of the bit stream separating apparatus 7100 and thebit stream merging apparatus 7200 have already been described.

The operation of the seventh preferred embodiment of the bit streamseparating and merging system 7000 will be described hereinlater, withreference to the i-th bit stream separating unit 7100 i, and the i-thbit stream merging unit 7200 i.

According to the present invention, the multi-output bit streamseparating apparatus 7100 is adapted to input an original MPEG-2 bitstream to separate into a plurality of transcoded MPEG-2 bit streams anda plurality of differential bit streams; and a multi-input bit streammerging apparatus 7200 is adapted to input a plurality of transcodedMPEG-2 bit streams and a plurality of differential bit streams toreconstruct the original MPEG-2 bit stream.

In this embodiment, the multi-output bit stream separating apparatus7100, however, is operated to input an original MPEG-2 bit stream toseparate into one transcoded MPEG-2 bit stream and a plurality ofdifferential bit streams; and a multi-input bit stream merging apparatus7200 is operated to input one transcoded MPEG-2 bit streams and aplurality of differential bit streams to reconstruct the original MPEG-2bit stream.

In the i-th bit stream merging unit 7200 i, the i-th inputting means INiis operated to input an (i−1)-th transcoded MPEG-2 bit stream 72.(i−1)therethrough from the (i−1)-th bit stream separating unit 7100 i−1.

The i-th bit stream converting means 111 i is operated to convert the(i−1)-th transcoded MPEG-2 bit stream 72.(i−1) inputted through the i-thinputting means INi to generate an i-th transcoded MPEG-2 bit stream72.i. The i-th bit stream converting means 111 i is also operated tooutput the i-th transcoded MPEG-2 bit stream 72.i thus generated to the(i+1)-th inputting means INi+1 of the (i+1)-th bit stream separatingunit 7100 i+1 through the interface i-th out1. The i-th bit streamconverting means 111 i is also operated to output the (i−1)-thtranscoded MPEG-2 bit stream 72.(i−1) and the i-th transcoded MPEG-2 bitstream 72.i to the i-th differential bit stream generating means 112 i.

The i-th differential bit stream generating means 112 i is operated toinput the (i−1)-th transcoded MPEG-2 bit stream 72.i−1 and the i-thtranscoded MPEG-2 bit stream 72.i from the i-th bit stream convertingmeans 111 i to generate an i-th differential bit stream 73.i on thebasis of the (i−1)-th second coefficient information obtained from theseries of (i−1)-th second picture information of the (i−1)-th transcodedMPEG-2 bit stream 72.i−1, and the i-th second coefficient informationobtained from the series of the i-th second picture information of thei-th transcoded MPEG-2 bit stream 72.i.

The i-th separating storage means 120 i is adapted to selectively storethe (i−1)-th transcoded MPEG-2 bit stream 72.i−1, the i-th transcodedMPEG-2 bit stream 72.i, and the i-th differential bit stream 73.i. Inthis embodiment, the i-th separating storage means 120 i is operated tostore the the i-th differential bit stream 73.i.

The i-th first transmission means 141 i is adapted to selectivelytransmit the (i−1)-th transcoded MPEG-2 bit stream 72.i−1, the i-thtranscoded MPEG-2 bit stream 72.i, and the i-th differential bit stream73.i to the i-th bit stream merging unit 7200 i.

In the i-th bit stream merging unit 7200 i, the i-th first receivingmeans 211 i is operated to receive a base bit stream, i.e., an i-thtranscoded MPEG-2 bit stream 72.i, from the (i+1)-th bit stream mergingunit 7200 i+1.

The i-th merging storage means 220 i is operated to store the base bitstream received by the i-th first receiving means 211 i.

The i-th request signal determining means 230 i is operated to determinea requested bit stream, and a request signal for the requested bitstream, i.e., an i-th differential bit stream 73.i, on the basis of thebase bit stream stored by the i-th merging storage means 220 i.

The i-th request signal transmission means 213 i is operated to transmitthe request signal for the requested bit stream determined by the i-threquest signal determining means 230 i to the i-th bit stream separatingunit 7100 i.

In the i-th bit stream separating unit 7100 i, the i-th request signalreceiving means 142 i is operated to receive the request signaltransmitted by the i-th request signal transmission means 213 i of thei-th bit stream merging unit 7200 i.

The i-th separating bit stream extracting means 130 i is operated toextract the requested bit stream, i.e., an i-th differential bit stream73.i, from among bit streams stored in the i-th separating storage means120 i in response to the request signal.

The i-th second transmission means 143 i is operated to transmit therequested bit stream extracted by the i-th separating bit streamextracting means 130 i to the i-th bit stream merging unit 7200 i.

In the i-th bit stream merging unit 7200 i, the i-th second receivingmeans 212 i is operated to receiving the requested bit streamtransmitted by the i-th second transmission means 143 i from the i-thbit stream separating unit 7100 i.

The i-th merging bit stream extracting means 241 i is operated toextract the base bit stream from the i-th merging storage means 220 i;

The i-th merging means 242 i is operated to merge the base bit stream,i.e., i-th transcoded MPEG-2 bit stream 72.i, extracted by the i-thmerging bit stream extracting means 241 i with the requested bit stream,i.e., an i-th differential bit stream 73.i, received by the i-th secondreceiving means 212 i on the basis of the i-th second coefficientinformation obtained from the series of second picture information ofthe i-th transcoded MPEG-2 bit stream 72.i, and the i-th differentialcoefficient information obtained from the i-th differential bit stream73.i to reconstruct the (i−1)-th transcoded MPEG-2 bit stream 72.(i−1).

The i-th outputting means OUTi is operated to input the reconstructed(i−1)-th transcoded MPEG-2 bit stream 72.(i−1) from the i-th mergingmeans 242 i to be outputted therethrough to the (i−1)-th bit streammerging unit 7200 i−1.

Furthermore, the number of the bit stream merging units 72001 to 7200 ncan be less than that of the bit stream separating units 71001 to 7100m, i.e., n is less than m.

This means that the n-th bit stream merging unit 7200 n can input then-th transcoded MPEG-2 bit stream-and n-th differential bit stream fromthe n-th bit stream separating unit 7100 n to reconstruct the (n−1)-thtranscoded MPEG-2 bit stream.

In the bit stream separating and merging system 7000 thus constructed,the multi-output bit stream separating apparatus 7100 can input, forinstance, an original MPEG-2 bit stream having a large bit rate toseparate into and transmit one or more transcoded MPEG-2 bit streams anda plurality of differential bit streams and the multi-input bit streammerging apparatus 7200 can input and merge the one or more transcodedMPEG-2 bit streams and the differential bit streams thus multiple-timesseparated to reconstruct the original MPEG-2 bit stream of the large bitrate. Each of the one or more transcoded MPEG-2 bit streams and thedifferential bit streams thus multiple-times separated has a bit ratelower than that of the original MPEG-2 bit stream. The bit streamseparating and merging system 7000 therefore makes it possible topromptly and reliably transmit and receive an original MPEG-2 bit streamhaving a large bit rate by transmitting and receiving a plurality oftranscoded MPEG-2 bit streams and a plurality of differential bitstreams multiple-times separated in place of the original MPEG-2 bitstream.

Furthermore, the i-th outputting means OUTi of the i-th bit streammerging unit 7200 i of the multi-input bit stream merging apparatus 7200according to the present invention can output the reconstructed (i−1)-thtranscoded MPEG-2 bit stream to an external device, such as a decoder.The multi-input bit stream merging apparatus 7200 thus constructed caninput one or more transcoded MPEG-2 bit streams and a plurality ofdifferential bit streams to output a plurality of transcoded MPEG-2 bitstreams, thereby making it possible for a user to selectively decode atranscoded MPEG-bit stream having a desired bit rate to reproduce anoriginal moving picture information of a desired picture quality.

VIII. Eighth Embodiment of Bit Stream Separating and Merging System 8000

There is provided an eighth preferred embodiment of the bit streamseparating and merging system 8000 comprising a multi-output bit streamseparating apparatus 8100 for inputting an original MPEG-2 bit stream toseparate into one or more transcoded MPEG-2 bit streams and a pluralityof differential bit streams; and a multi-input bit stream mergingapparatus 8200 for inputting a one or more transcoded MPEG-2 bit streamsand a plurality of differential bit streams to reconstruct the originalMPEG-2 bit stream.

The multi-output bit stream separating apparatus 8100 comprises aplurality of bit stream separating units 81001 to 8100 m including a 1stbit stream separating unit 81001 up to a m-th bit stream separating unit8100 m wherein m is an integer not less than two.

The multi-input bit stream merging apparatus 8200 comprises a pluralityof bit stream merging units 82001 to 8200 n including a 1st bit streammerging unit 81001 up to a n-th bit stream merging unit 8100 n wherein nis an integer not less than two.

The multi-output bit stream separating apparatus according to thepresent invention may comprise one or more of bit stream separatingunits which are the same in construction as any one or more of the bitstream separating apparatuses 1100, 2100, 3100, 4100, 5100, and 6100.

Similarly, the multi-input bit stream merging apparatus according to thepresent invention may comprise one or more of bit stream merging unitswhich are the same in construction as any one or more of the bit streammerging apparatus 1200, 1200, 2200, 3200, 4200, 5200, and 6200.

The multi-output bit stream separating apparatus 8100 comprises aplurality of bit stream separating units 81001 to 8100 m. Any one of thebit stream separating units 81001 to 8100 m is hereinlater referred toas i-th bit stream separating unit 8100 i wherein i is an integer equalto or less than m.

The i-th bit stream separating units of the bit stream separating units81001 to 8100 m of the multi-output bit stream separating apparatus 8100is same in the construction as the bit stream separating apparatus 2100shown in FIG. 6 as comprising as comprising an inputting terminal INi,i-th bit stream converting means 111 i, i-th differential bit streamgenerating means 112 i, i-th separating storage means 120 i, i-th firsttransmission means 141 i, i-th request signal receiving means 142 i,i-th bit stream extracting means 130 i, i-th second transmission means143 i, and i-th outputting interface OUTi.

The multi-input bit stream merging apparatus 8200 comprises a pluralityof bit stream merging units 82001 to 8200 m. Any one of the bit streammerging units 82001 to 8200 m is hereinlater referred to as i-th bitstream merging unit 8200 i wherein i is an integer equal to or less thanm.

The i-th bit stream merging units of the bit stream merging units 82001to 8200 m of the multi-output bit stream merging apparatus 8200 is samein the construction as the bit stream merging apparatus 2200 shown inFIG. 6 as comprising inputting interfaces, i-th first receiving means211 i, i-th merging storage means 220 i, i-th decoding means 225 i, i-threquest signal determining means 230 i, i-th request signal transmissionmeans 213 i, i-th second receiving means 212 i, i-th merging bit streamextracting means 241 i, i-th merging means 242 i, and outputting meansOUTi.

This means that the bit stream separating units 81001 to 8100 n−1 areadapted to store differential bit streams in their respective separatingstorage means and transmit transcoded MPEG-2 bit streams to subsequentlyplaced bit stream separating units 82002 to 8200 n. The bit streamseparating unit n is adapted to transmit the transcoded MPEG-2 bitstream to the bit stream merging unit n. The bit stream merging unit8200 n is adapted to receive the transcoded MPEG-2 bit stream and thedifferential bit stream from the bit stream separating unit n, and thebit stream merging units 8200 n−1 to 82001 are adapted to receive thetranscoded MPEG-2 bit streams from the previously placed bit streammerging units 8200 n to 82002 and bit streams from the respective bitstream merging units 8200 n−1 to 82001.

The operation of the bit stream separating and merging system 8000according to the present invention will be described hereinlater withreference to the i-th bit stream separating unit 8100 i, and the i-thbit stream merging unit 8200 i. The operation of the bit streamseparating and merging system 8000 as those of the bit stream separatingand merging system 6000 will be omitted for avoiding tedious repetition.The same constitutional elements are simply represented by the samereference numerals.

In the i-th bit stream separating unit 8100 i, the i-th inputtingterminal INi is operated to receive an (i−1)-th transcoded MPEG-2 bitstream 72.(i−1) from a (i−1)th bit stream separating unit 8100 i−1.

The i-th bit stream converting means 111 i is operated to convert the(i−1)-th transcoded MPEG-2 bit stream 72.(i−1) inputted through the i-thinputting means INI to generate an i-th transcoded MPEG-2 bit stream72.i. The i-th bit stream converting means 111 i is operated to outputthe i-th transcoded MPEG-2 bit stream 72.i thus generated to the(i+1)-th inputting means INi+1 of the (i+1)-th bit stream separatingunit 8100 i+1 through the interface out1. The i-th bit stream convertingmeans 111 i is also operated to output the (i−1)-th transcoded MPEG-2bit stream 72.(i−1) and the i-th transcoded MPEG-2 bit stream 72.i tothe i-th differential bit stream generating means 112 i.

The i-th differential bit stream generating means 112 i is operated toinput the (i−1)-th transcoded MPEG-2 bit stream 72.i−1 and the i-thtranscoded MPEG-2 bit stream 72.i from the i-th bit stream convertingmeans 111 i to generate an i-th differential bit stream 73.i on thebasis of the (i−1)-th second coefficient information obtained from theseries of (i−1)-th second picture information of the (i−1)-th transcodedMPEG-2 bit stream 72.i−1, and the i-th second coefficient informationobtained from the series of the i-th second picture information of thei-th transcoded MPEG-2 bit stream 72.i.

The i-th separating storage means 120 i is operated to store the i-thdifferential bit stream 73.i generated by the i-th differential bitstream generating means 112 i.

In the i-th bit stream merging unit 8200 i, the i-th first receivingmeans 211 i is operated to receive the i-th transcoded MPEG-2 bit stream72.i from outputting means OUTi+1 of the (i+1)-th bit stream mergingunit 8200 i+1.

The i-th decoding means 225 i is operated to decode the i-th transcodedMPEG-2 bit stream 72.i.

The i-th merging storage means 220 i is operated to store the i-thtranscoded MPEG-2 bit stream 72.i received by the i-th first receivingmeans 211 i.

The i-th request signal determining means 230 i is operated to determinea requested differential bit stream and a request signal for therequested differential bit stream on the basis of the i-th transcodedMPEG-2 bit stream 72.i stored by the i-th merging storage means 220 i.

The i-th request signal transmission means 213 i is operated to transmitthe request signal for the requested differential bit stream determinedby the i-th request signal determining means 230 i.

In the i-th bit stream separating unit 8100 i, the i-th request signalreceiving means 142 i is operated to receive the request signaltransmitted by the i-th request signal transmission means 213 i.

The i-th separating bit stream extracting means 130 i is operated toextract the requested differential bit stream from the i-th separatingstorage means 120 i in response to the request signal.

The i-th second transmission means 143 i is operated to transmit therequested differential bit stream extracted by the i-th separating bitstream extracting means 130 i to the i-th bit stream merging unit 8200i.

In the i-th bit stream merging unit 8200 i, the i-th second receivingmeans 212 i is operated to receive the requested differential bit streamtransmitted by the i-th second transmission means 143 i from the i-thbit stream separating unit 8100 i.

The i-th merging bit stream extracting means 241 i is operated toextract the i-th transcoded MPEG-2 bit stream 72.i from the i-th mergingstorage means 220 i.

The i-th merging means 242 i is operated to merge the i-th transcodedMPEG-2 bit stream 72.i extracted by the i-th merging bit streamextracting means 241 i with the requested differential bit streamreceived by the i-th second receiving means 212 i to reconstruct the(i−1)-th transcoded MPEG-2 bit stream to be outputted to the outputtingmeans OUT1 i.

The outputting means OUTi is operated to input the the (i−1)-thtranscoded MPEG-2 bit stream thus reconstructed to an (i−1)-th bitstream merging apparatus 8200 i−1.

As will be seen from the foregoing description, the bit streamseparating and merging system 8000 thus constructed makes it possiblefor a user to receive one or more transcoded MPEG-2 bit streams at bitrates much lower than that of the original MPEG-2 bit stream to decode,reproduce, and preview low-quality picture information, and laterreceive a plurality of differential bit streams at bit rates much lowerthan that of the original MPEG-2 bit stream to reproduce high-qualitypicture information in combining with the transcoded MPEG-2 bit streamsearlier received thereby effectively utilize the transcoded MPEG-2 bitstreams and the transmitting paths.

According to the present invention, the bit stream separating andmerging system may comprise multi-output bit stream separating apparatusincluding one or more of bit stream separating units same inconstruction as any one or more of the first to the sixth embodiment ofbit stream separating apparatuses 1100, 2100, 3100, 4100, 5100, and 6100and the multi-input bit stream merging apparatus including one or moreof bit stream merging units which are the same in construction as anyone or more of the first to the sixth embodiment of bit stream mergingapparatus 1200, 1200, 2200, 3200, 4200, 5200, and 6200.

The many features and advantages of the invention are apparent from thedetailed specification, and thus it is intended by the appended claimsto cover all such features and advantages of the invention which fallwithin the true spirit and scope thereof. Further, since numerousmodifications and changes will readily occur to those skilled in theart, it is not desired to limit the invention to the exact constructionand operation illustrated and described herein, and accordingly, allsuitable modifications and equivalents may be construed as beingencompassed within the scope of the invention.

1-25. (canceled)
 26. A multi-output coded signal separating apparatusfor inputting a first coded moving picture sequence signal to separateinto a plurality of second coded moving picture sequence signals and aplurality of differential coded moving picture sequence signalscomprising: a plurality of coded signal separating units including a 1stcoded signal separating unit up to a m-th coded signal separating unitwherein m is an integer not less than two; said 1st coded signalseparating unit being operative to input said first coded moving picturesequence signal to separate into a 1st second coded moving picturesequence signal and a 1st differential coded moving picture sequencesignal, said 1st differential coded moving picture sequence signal beinga difference between said first coded moving picture sequence signal andsaid 1st second coded moving picture sequence signal, and said i-thcoded signal separating unit being operative to input an (i−1)-th secondcoded moving picture sequence signal to separate into an i-th secondcoded moving picture sequence signal and an i-th differential codedmoving picture sequence signal, said i-th differential coded movingpicture sequence signal being a difference between said (i−1)-th secondcoded moving picture sequence signal and said i-th second coded movingpicture sequence signal wherein i is an integer equal to or less than m,whereby said 1st coded signal separating unit includes: 1st inputtingmeans for inputting said first coded moving picture sequence signaltherethrough, said first coded moving picture sequence signal generatedas a result of encoding original moving picture sequence signal andconsisting of a series of first picture information having firstcoefficient information, said first coefficient information including amatrix of first coefficients; 1st coded signal converting means forconverting said first coded moving picture sequence signal inputtedthrough said 1st inputting means to generate a 1st second coded movingpicture sequence signal, said 1st second coded moving picture sequencesignal consisting of a series of 1st second picture information having1st second coefficient information, said 1st second coefficientinformation including a matrix of 1st second coefficients, each of saidfirst coded moving picture sequence signal, and said 1st second codedmoving picture sequence signal is in the form of a hierarchicalstructure including one or more sequence layers each having a pluralityof screens sharing common information, one or more picture layers eachhaving a plurality of slices sharing common information with respect toone of said screens, one or more slice layers each having a plurality ofmacroblocks with respect to one of said slices, one or more macroblocklayers each having a plurality of blocks with respect to one of saidmacroblocks, and one or more block layers each having block informationwith respect to one of said blocks; 1st differential coded signalgenerating means for inputting said first coded moving picture sequencesignal and said 1st second coded moving picture sequence signal fromsaid 1st coded signal converting means to generate a 1st differentialcoded moving picture sequence signal on the basis of said firstcoefficient information obtained from said series of first pictureinformation of said first coded moving picture sequence signal, and said1st second coefficient information obtained from said series of said 1stsecond picture information of said 1st second coded moving picturesequence signal, said 1st differential coded moving picture sequencesignal being a difference between said first coded moving picturesequence signal and said 1st second coded moving picture sequencesignal; 1st separating storage means for selectively storing said firstcoded moving picture sequence signal, said 1st second coded movingpicture sequence signal, and said 1st differential coded moving picturesequence signal; 1st first transmission means for selectivelytransmitting said first coded moving picture sequence signal, said 1stsecond coded moving picture sequence signal, and said 1st differentialcoded moving picture sequence signal; 1st request signal receiving meansfor receiving a request signal indicative of a requested coded movingpicture sequence signal to be transmitted, said request signalindicative of said requested coded moving picture sequence signal beingdetermined on the basis of said first coded moving picture sequencesignal, said 1st second coded moving picture sequence signal, or said1st differential coded moving picture sequence signal; 1st separatingcoded signal extracting means for extracting said requested coded movingpicture sequence signal from said 1st separating storage means inresponse to said request signal; and 1st second transmission means fortransmitting said requested coded moving picture sequence signalextracted by said 1st separating coded signal extracting means, and saidi-th coded signal separating unit includes: i-th inputting means forinputting said (i−1)-th second coded moving picture sequence signaltherethrough from said (i−1)-th coded signal separating unit, said(i−1)-th second coded moving picture sequence signal generated as aresult of encoding original moving picture sequence signal andconsisting of a series of (i−1)-th second picture information having(i−1)-th second coefficient information, said (i−1)-th secondcoefficient information including a matrix of (i−1)-th secondcoefficients; i-th coded signal converting means for converting said(i−1)-th second coded moving picture sequence signal inputted throughsaid i-th inputting means to generate said i-th second coded movingpicture sequence signal, said i-th second coded moving picture sequencesignal consisting of a series of i-th second picture information havingi-th second coefficient information, said i-th second coefficientinformation including a matrix of i-th second coefficients, each of said(i−1)-th second coded moving picture sequence signal, and said i-thsecond coded moving picture sequence signal is in the form of ahierarchical structure including one or more sequence layers each havinga plurality of screens sharing common information, one or more picturelayers each having a plurality of slices sharing common information withrespect to one of said screens, one or more slice layers each having aplurality of macroblocks with respect to one of said slices, one or moremacroblock layers each having a plurality of blocks with respect to oneof said macroblocks, and one or more block layers each having blockinformation with respect to one of said blocks; i-th differential codedsignal generating means for inputting said (i−1)-th second coded movingpicture sequence signal and said i-th second coded moving picturesequence signal from said i-th coded signal converting means to generatean i-th differential coded moving picture sequence signal on the basisof said (i−1)-th second coefficient information obtained from saidseries of (i−1)-th second picture information of said (i−1)-th secondcoded moving picture sequence signal, and said i-th second coefficientinformation obtained from said series of said i-th second pictureinformation of said i-th second coded moving picture sequence signal,said i-th differential coded moving picture sequence signal being adifference between said (i−1)-th second coded moving picture sequencesignal and said i-th second coded moving picture sequence signal; i-thseparating storage means for selectively storing said (i−1)-th secondcoded moving picture sequence signal, said i-th second coded movingpicture sequence signal, and said i-th differential coded moving picturesequence signal; i-th first transmission means for selectivelytransmitting said (i−1)-th second coded moving picture sequence signal,said i-th second coded moving picture sequence signal, and said i-thdifferential coded moving picture sequence signal; i-th request signalreceiving means for receiving a request signal indicative of a requestedcoded moving picture sequence signal to be transmitted, said requestsignal indicative of said requested coded moving picture sequence signalbeing determined on the basis of said (i−1)-th second coded movingpicture sequence signal, said i-th second coded moving picture sequencesignal, or said i-th differential coded moving picture sequence signal;i-th separating coded signal extracting means for extracting saidrequested coded moving picture sequence signal from said i-th separatingstorage means in response to said request signal; and i-th secondtransmission means for transmitting said requested coded moving picturesequence signal extracted by said i-th separating coded signalextracting means.
 27. A multi-input coded signal merging apparatus forinputting a plurality of second coded moving picture sequence signalsand a plurality of differential coded moving picture sequence signals toreconstruct a first coded moving picture sequence signal comprising: aplurality of said coded signal merging units including a 1st codedsignal merging unit up to a m-th coded signal merging unit wherein n isan integer not less than two, said i-th coded signal merging unit beingoperative to input a i-th second coded moving picture sequence signaland a i-th differential coded moving picture sequence signal toreconstruct an (i−1)-th second coded moving picture sequence signalwherein i is an integer equal to or less than n, said i-th second codedmoving picture sequence signal generated as a result of transcoding said(i−1)-th second coded moving picture sequence signal and consisting of aseries of i-th second picture information having i-th second coefficientinformation, said i-th second coefficient information including a matrixof i-th second coefficients, said (i−1)-th second coded moving picturesequence signal generated as a result of encoding original movingpicture sequence signal and consisting of a series of (i−1)-th secondpicture information having (i−1)-th second coefficient information, said(i−1)-th second coefficient information including a matrix of (i−1)-thsecond coefficients, said i-th differential coded moving picturesequence signal being a difference between said i-th second coded movingpicture sequence signal and said (i−1)-th second coded moving picturesequence signal, said i-th differential coded moving picture sequencesignal including i-th differential coefficient information between saidi-th second coefficient information and said (i−1)-th second coefficientinformation, each of said i-th second coded moving picture sequencesignal, said (i−1)-th second coded moving picture sequence signal, andsaid i-th differential coded moving picture sequence signal is in theform of a hierarchical structure including one or more sequence layerseach having a plurality of screens sharing common information, one ormore picture layers each having a plurality of slices sharing commoninformation with respect to one of said screens, one or more slicelayers each having a plurality of macroblocks with respect to one ofsaid slices, one or more macroblock layers each having a plurality ofblocks with respect to one of said macroblocks, and one or more blocklayers each having block information with respect to one of said blocks,and said 1st coded signal merging unit being operative to input said 1stsecond coded moving picture sequence signal and said 1st differentialcoded moving picture sequence signal to reconstruct said first codedmoving picture sequence signal, whereby said i-th coded signal mergingunit includes: i-th first receiving means for receiving a base codedmoving picture sequence signal, said base coded moving picture sequencesignal being any one of said i-th second coded moving picture sequencesignal, said (i−1)-th second coded moving picture sequence signal, andsaid i-th differential coded moving picture sequence signal; i-thmerging storage means for storing said base coded moving picturesequence signal received by said i-th first receiving means; i-threquest signal determining means for determining a request signal for arequested coded moving picture sequence signal on the basis of said basecoded moving picture sequence signal stored by said i-th merging storagemeans; i-th request signal transmission means for transmitting saidrequest signal for said requested coded moving picture sequence signaldetermined by said i-th request signal determining means; i-th secondreceiving means for receiving said requested coded moving picturesequence signal; i-th merging coded signal extracting means forextracting said base coded moving picture sequence signal from said i-thmerging storage means; i-th merging means for merging said base codedmoving picture sequence signal extracted by said i-th merging codedsignal extracting means with said requested coded moving picturesequence signal received by said i-th second receiving means toreconstruct said (i−1)-th second coded moving picture sequence signal onthe basis of i-th said second coefficient information obtained from saidseries of i-th second picture information of said i-th second codedmoving picture sequence signal, and said i-th differential coefficientinformation obtained from said i-th differential coded signal; and i-thoutputting means for inputting said reconstructed i-th second codedmoving picture sequence signal from said i-th merging means to beoutputted therethrough, said 1st coded signal merging unit includes: 1stfirst receiving means for receiving a base coded moving picture sequencesignal, said base coded moving picture sequence signal being any one ofsaid first coded moving picture sequence signal, said 1st second codedmoving picture sequence signal, and said 1st differential coded movingpicture sequence signal; 1st merging storage means for storing said basecoded moving picture sequence signal received by said 1st firstreceiving means; 1st request signal determining means for determining arequest signal for a requested coded moving picture sequence signal onthe basis of said base coded moving picture sequence signal stored bysaid 1st merging storage means; 1st request signal transmission meansfor transmitting said request signal for said requested coded movingpicture sequence signal determined by said 1st request signaldetermining means; 1st second receiving means for receiving saidrequested coded moving picture sequence signal; 1st merging coded signalextracting means for extracting said base coded moving picture sequencesignal from said 1st merging storage means; 1st merging means formerging said base coded moving picture sequence signal extracted by said1st merging coded signal extracting means with said requested codedmoving picture sequence signal received by said 1st second receivingmeans to reconstruct said first coded moving picture sequence signal onthe basis of said 1st second coefficient information obtained from saidseries of second picture information of said 1st second coded movingpicture sequence signal, and said 1st differential coefficientinformation obtained from said 1st differential coded signal; and 1stoutputting means for inputting said reconstructed first coded movingpicture sequence signal from said 1st merging means to be outputtedtherethrough.
 28. A multi-output coded signal separating apparatus asset forth in claim 26, in said i-th coded signal separating units saidi-th separating storage means is operative to store said (i−1)-thdifferential coded moving picture sequence signal generated by said i-thdifferential coded signal generating means, said i-th first transmissionmeans is operative to transmit said (i−1)-th second coded moving picturesequence signal generated by said i-th coded signal converting means,said i-th request signal receiving means is operative to receive saidrequest signal indicative of a requested (i−1)-th differential codedmoving picture sequence signal to be transmitted, said request signalindicative of said requested (i−1)-th differential coded moving picturesequence signal being determined on the basis of said (i−1)-th secondcoded moving picture sequence signal, said i-th separating coded signalextracting means is operative to extract said requested (i−1)-thdifferential coded moving picture sequence signal from said i-thseparating storage means in response to said request signal, and saidi-th second transmission means is operative to transmit said requested(i−1)-th differential coded moving picture sequence signal extracted bysaid i-th separating coded signal extracting means whereby saidmulti-output coded signal separating apparatus is operative to input afirst coded moving picture sequence signal to separate into a pluralityof second coded moving picture sequence signals and a plurality ofdifferential coded moving picture sequence signals.
 29. A multi-inputcoded signal merging apparatus as set forth in claim 27, in said i-thcoded signal merging unit, said i-th first receiving means is operativeto receive said i-th second coded moving picture sequence signal, saidi-th merging storage means is operative to store said i-th second codedmoving picture sequence signal received by said i-th first receivingmeans, said i-th request signal determining means is operative todetermine a request signal for a requested differential coded movingpicture sequence signal on the basis of said i-th second coded movingpicture sequence signal stored by said i-th merging storage means, saidi-th request signal transmission means is operative to transmit saidrequest signal for said requested differential coded moving picturesequence signal determined by said i-th request signal determiningmeans, said i-th second receiving means is operative to receive saidrequested differential coded moving picture sequence signal, said i-thmerging coded signal extracting means is operative to extract said i-thsecond coded moving picture sequence signal from said i-th mergingstorage means, and said i-th merging means is operative to merge saidi-th second coded moving picture sequence signal extracted by said i-thmerging coded signal extracting means with said requested differentialcoded moving picture sequence signal received by said i-th secondreceiving means to reconstruct said (i−1)-th second coded moving picturesequence signal wherein said 0-th second coded moving picture sequencesignal is said first coded moving picture sequence signal.
 30. A codedsignal separating and merging system comprising: a multi-output codedsignal separating apparatus for inputting a first coded moving picturesequence signal to separate into a plurality of second coded movingpicture sequence signals and a plurality of differential coded movingpicture sequence signals; and a multi-input coded signal mergingapparatus for inputting a plurality of second coded moving picturesequence signals and a plurality of differential coded moving picturesequence signals to reconstruct said first coded moving picture sequencesignal, said multi-output coded signal separating apparatus including: aplurality of coded signal separating units including a 1st coded signalseparating unit up to a m-th coded signal separating unit wherein m isan integer not less than two; said multi-input coded signal mergingapparatus including: a plurality of coded signal merging units includinga 1st coded signal merging unit up to a m-th coded signal merging unitwherein n is an integer not less than two and equal to or less than saidm, said i-th coded signal separating unit including: i-th inputtingmeans for inputting an (i−1)-th second coded moving picture sequencesignal therethrough from said (i−1)-th coded signal separating unit,said (i−1)-th second coded moving picture sequence signal generated as aresult of encoding original moving picture sequence signal andconsisting of a series of (i−1)-th second picture information having(i−1)-th second coefficient information, said (i−1)-th secondcoefficient information including a matrix of (i−1)-th secondcoefficients wherein i is an integer equal to or less than m, and 0-thsecond coded moving picture sequence signal is said first coded movingpicture sequence signal; i-th coded signal converting means forconverting said (i−1)-th second coded moving picture sequence signalinputted through said i-th inputting means to generate an i-th secondcoded moving picture sequence signal, said i-th second coded movingpicture sequence signal consisting of a series of i-th second pictureinformation having i-th second coefficient information, said i-th secondcoefficient information including a matrix of second coefficients, eachof said (i−1)-th second coded moving picture sequence signal, and saidi-th second coded moving picture sequence signal is in the form of ahierarchical structure including one or more sequence layers each havinga plurality of screens sharing common information, one or more picturelayers each having a plurality of slices sharing common information withrespect to one of said screens, one or more slice layers each having aplurality of macroblocks with respect to one of said slices, one or moremacroblock layers each having a plurality of blocks with respect to oneof said macroblocks, and one or more block layers each having blockinformation with respect to one of said blocks; i-th differential codedsignal generating means for inputting said (i−1)-th second coded movingpicture sequence signal and said i-th second coded moving picturesequence signal from said i-th coded signal converting means to generatean i-th differential coded moving picture sequence signal on the basisof said (i−1)-th second coefficient information obtained from saidseries of (i−1)-th second picture information of said (i−1)-th secondcoded moving picture sequence signal, and said i-th second coefficientinformation obtained from said series of said i-th second pictureinformation of said i-th second coded moving picture sequence signal,said i-th differential coded moving picture sequence signal being adifference between said (i−1)-th second coded moving picture sequencesignal and said i-th second coded moving picture sequence signal; i-thseparating storage means for selectively storing said (i−1)-th secondcoded moving picture sequence signal, said i-th second coded movingpicture sequence signal, and said i-th differential coded moving picturesequence signal; and i-th first transmission means for selectivelytransmitting said (i−1)-th second coded moving picture sequence signal,said i-th second coded moving picture sequence signal, and said i-thdifferential coded moving picture sequence signal to said i-th codedsignal merging unit; said i-th coded signal merging unit including: i-thfirst receiving means for receiving a base coded moving picture sequencesignal from said i-th coded signal separating unit or said (i+1)-thcoded signal merging unit (6200 i+1), said base coded moving picturesequence signal being any one of said (i−1)-th second coded movingpicture sequence signal, said i-th second coded moving picture sequencesignal, and said i-th differential coded moving picture sequence signal;i-th merging storage means for storing said base coded moving picturesequence signal received by said i-th first receiving means; i-threquest signal determining means for determining a request signal for arequested coded moving picture sequence signal on the basis of said basecoded moving picture sequence signal stored by said i-th merging storagemeans; and i-th request signal transmission means for transmitting saidrequest signal for said requested coded moving picture sequence signaldetermined by said i-th request signal determining means to said i-thcoded signal separating unit; whereby said i-th coded signal separatingunit further includes: i-th request signal receiving means for receivingsaid request signal transmitted by said i-th request signal transmissionmeans from said i-th coded signal merging unit; i-th separating codedsignal extracting means for extracting said requested coded movingpicture sequence signal from said i-th separating storage means inresponse to said request signal; and i-th second transmission means fortransmitting said requested coded moving picture sequence signalextracted by said i-th separating coded signal extracting means to saidi-th coded signal merging unit; said i-th coded signal merging unitincludes: i-th second receiving means for receiving said requested codedmoving picture sequence signal transmitted by said i-th secondtransmission means from said i-th coded signal separating unit; i-thmerging coded signal extracting means for extracting said base codedmoving picture sequence signal from said i-th merging storage means;i-th merging means for merging said base coded moving picture sequencesignal extracted by said i-th merging coded signal extracting means withsaid requested coded moving picture sequence signal received by saidi-th second receiving means on the basis of said i-th second coefficientinformation obtained from said series of second picture information ofsaid i-th second coded moving picture sequence signal, and said i-thdifferential coefficient information obtained from said i-thdifferential coded signal to reconstruct said (i−1)-th second codedmoving picture sequence signal; and i-th outputting means for inputtingsaid reconstructed (i−1)-th second coded moving picture sequence signalfrom said i-th merging means to be outputted therethrough.
 31. A codedsignal separating and merging system as set forth in claim 30 in whichsaid i-th separating storage means of said i-th coded signal separatingunit is operative to store said i-th differential coded moving picturesequence signal generated by said i-th differential coded signalgenerating means, said i-th first transmission means is operative totransmit said i-th second coded moving picture sequence signal generatedby said i-th coded signal converting means, said i-th first receivingmeans of said i-th coded signal merging unit is operative to receivesaid i-th second coded moving picture sequence signal from said (i+1)-thcoded signal merging unit, said i-th merging storage means is operativeto store said i-th second coded moving picture sequence signal receivedby said i-th first receiving means, said i-th request signal determiningmeans is operative to determine a request signal for a requesteddifferential coded moving picture sequence signal on the basis of saidi-th second coded moving picture sequence signal stored by said i-thmerging storage means, said i-th request signal transmission means isoperative to transmit said request signal for said requesteddifferential coded moving picture sequence signal determined by saidi-th request signal determining means, said i-th request signalreceiving means of said i-th coded signal separating unit is operativeto receive said request signal transmitted by said i-th request signaltransmission means, said i-th separating coded signal extracting meansis operative to extract said requested differential coded moving picturesequence signal from said i-th separating storage means in response tosaid request signal, said i-th second transmission means is operative totransmit said requested differential coded moving picture sequencesignal extracted by said i-th separating coded signal extracting meansto said i-th coded signal merging unit, said i-th second receiving meansof said i-th coded signal merging unit is operative to receive saidrequested differential coded moving picture sequence signal transmittedby said i-th second transmission means from said i-th coded signalseparating unit, said i-th merging coded signal extracting means isoperative to extract said i-th second coded moving picture sequencesignal from said i-th merging storage means, and said i-th merging meansis operative to merge said i-th second coded moving picture sequencesignal extracted by said i-th merging coded signal extracting means withsaid requested differential coded moving picture sequence signalreceived by said i-th second receiving means to reconstruct said firstcoded moving picture sequence signal. 32-56. (canceled)
 57. Amulti-output coded signal separating method for inputting a first codedmoving picture sequence signal to separate into a plurality of secondcoded moving picture sequence signals and a plurality of differentialcoded moving picture sequence signals comprising a plurality of steps(A1 to Am) including a step (A1) up to a step (Am) wherein m is aninteger not less than two; said step (A1) is the step of inputting saidfirst coded moving picture sequence signal to separate into a 1st secondcoded moving picture sequence signal and a 1st differential coded movingpicture sequence signal, said 1st differential coded moving picturesequence signal being a difference between said first coded movingpicture sequence signal and said 1st second coded moving picturesequence signal, and said step (Ai) is the step of inputting an (i−1)-thsecond coded moving picture sequence signal to separate into an i-thsecond coded moving picture sequence signal and an i-th differentialcoded moving picture sequence signal, said i-th differential codedmoving picture sequence signal being a difference between said (i−1)-thsecond coded moving picture sequence signal and said i-th second codedmoving picture sequence signal wherein i is an integer equal to or lessthan m, whereby said step (A1) includes the steps of: (A1-1) inputtingsaid first coded moving picture sequence signal therethrough, said firstcoded moving picture sequence signal generated as a result of encodingoriginal moving picture sequence signal and consisting of a series offirst picture information having first coefficient information, saidfirst coefficient information including a matrix of first coefficients;(A1-2) converting said first coded moving picture sequence signalinputted in said step (A1-1) to generate a 1st second coded movingpicture sequence signal, said 1st second coded moving picture sequencesignal consisting of a series of 1st second picture information having1st second coefficient information, said 1st second coefficientinformation including a matrix of 1st second coefficients, each of saidfirst coded moving picture sequence signal, and said 1st second codedmoving picture sequence signal is in the form of a hierarchicalstructure including one or more sequence layers each having a pluralityof screens sharing common information, one or more picture layers eachhaving a plurality of slices sharing common information with respect toone of said screens, one or more slice layers each having a plurality ofmacroblocks with respect to one of said slices, one or more macroblocklayers each having a plurality of blocks with respect to one of saidmacroblocks, and one or more block layers each having block informationwith respect to one of said blocks; (A1-3) inputting said first codedmoving picture sequence signal and said 1st second coded moving picturesequence signal from said step (A1-2) to generate a 1st differentialcoded moving picture sequence signal on the basis of said firstcoefficient information obtained from said series of first pictureinformation of said first coded moving picture sequence signal, and said1st second coefficient information obtained from said series of said 1stsecond picture information of said 1st second coded moving picturesequence signal, said 1st differential coded moving picture sequencesignal being a difference between said first coded moving picturesequence signal and said 1st second coded moving picture sequencesignal; (A1-4) selectively storing said first coded moving picturesequence signal, said 1st second coded moving picture sequence signal,and said 1st differential coded moving picture sequence signal; (A1-5)selectively transmitting said first coded moving picture sequencesignal, said 1st second coded moving picture sequence signal, and said1st differential coded moving picture sequence signal; (A1-6) receivinga request signal indicative of a requested coded moving picture sequencesignal to be transmitted, said request signal indicative of saidrequested coded moving picture sequence signal being determined on thebasis of said first coded moving picture sequence signal, said 1stsecond coded moving picture sequence signal, or said 1st differentialcoded moving picture sequence signal; (A1-7) extracting said requestedcoded moving picture sequence signal from among coded moving picturesequence signals stored in said step (A1-4) in response to said requestsignal; and (A1-8) transmitting said requested coded moving picturesequence signal extracted in said step (A1-7), and said step (Ai)includes the steps of: (Ai-1) inputting said (i−1)-th second codedmoving picture sequence signal therethrough from said step (A(i−1)),said (i−1)-th second coded moving picture sequence signal generated as aresult of encoding original moving picture sequence signal andconsisting of a series of (i−1)-th second picture information having(i−1)-th second coefficient information, said (i−1)-th secondcoefficient information including a matrix of (i−1)-th secondcoefficients; (Ai-2) converting said (i−1)-th second coded movingpicture sequence signal inputted through said step (Ai-1) to generatesaid i-th second coded moving picture sequence signal, said i-th secondcoded moving picture sequence signal consisting of a series of i-thsecond picture information having i-th second coefficient information,said i-th second coefficient information including a matrix of i-thsecond coefficients, each of said (i−1)-th second coded moving picturesequence signal, and said i-th second coded moving picture sequencesignal is in the form of a hierarchical structure including one or moresequence layers each having a plurality of screens sharing commoninformation, one or more picture layers each having a plurality ofslices sharing common information with respect to one of said screens,one or more slice layers each having a plurality of macroblocks withrespect to one of said slices, one or more macroblock layers each havinga plurality of blocks with respect to one of said macroblocks, and oneor more block layers each having block information with respect to oneof said blocks; (Ai-3) inputting said (i−1)-th second coded movingpicture sequence signal and said i-th second coded moving picturesequence signal from said step (Ai-2) to generate an i-th differentialcoded moving picture sequence signal on the basis of said (i−1)-thsecond coefficient information obtained from said series of (i−1)-thsecond picture information of said (i−1)-th second coded moving picturesequence signal, and said i-th second coefficient information obtainedfrom said series of said i-th second picture information of said i-thsecond coded moving picture sequence signal, said i-th differentialcoded moving picture sequence signal being a difference between said(i−1)-th second coded moving picture sequence signal and said i-thsecond coded moving picture sequence signal; (Ai-4) selectively storingsaid (i−1)-th second coded moving picture sequence signal, said i-thsecond coded moving picture sequence signal, and said i-th differentialcoded moving picture sequence signal; (Ai-5) selectively transmittingsaid (i−1)-th second coded moving picture sequence signal, said i-thsecond coded moving picture sequence signal, and said i-th differentialcoded moving picture sequence signal; (Ai-6) receiving a request signalindicative of a requested coded moving picture sequence signal to betransmitted, said request signal indicative of said requested codedmoving picture sequence signal being determined on the basis of said(i−1)-th second coded moving picture sequence signal, said i-th secondcoded moving picture sequence signal, or said i-th differential codedmoving picture sequence signal; (Ai-7) extracting said requested codedmoving picture sequence signal from among coded moving picture sequencesignals stored in said step (Ai-4) in response to said request signal;and (Ai-8) transmitting said requested coded moving picture sequencesignal extracted in said step (Ai-7).
 58. A multi-input coded signalmerging method for inputting a plurality of second coded moving picturesequence signals and a plurality of differential coded moving picturesequence signals to reconstruct a first coded moving picture sequencesignal comprising a plurality of steps (B1 to Bn) including a step (B1)up to a step (Bn) wherein n is an integer not less than two, said step(Bi) has the step of inputting a i-th second coded moving picturesequence signal and a i-th differential coded moving picture sequencesignal to reconstruct an (i−1)-th second coded moving picture sequencesignal wherein i is an integer equal to or less than n, said i-th secondcoded moving picture sequence signal generated as a result oftranscoding said (i−1)-th second coded moving picture sequence signaland consisting of a series of i-th second picture information havingi-th second coefficient information, said i-th second coefficientinformation including a matrix of i-th second coefficients, said(i−1)-th second coded moving picture sequence signal generated as aresult of encoding original moving picture sequence signal andconsisting of a series of (i−1)-th second picture information having(i−1)-th second coefficient information, said (i−1)-th secondcoefficient information including a matrix of (i−1)-th secondcoefficients, said i-th differential coded moving picture sequencesignal being a difference between said i-th second coded moving picturesequence signal and said (i−1)-th second coded moving picture sequencesignal, said i-th differential coded moving picture sequence signalincluding i-th differential coefficient information between said i-thsecond coefficient information and said (i−1)-th second coefficientinformation, each of said i-th second coded moving picture sequencesignal, said (i−1)-th second coded moving picture sequence signal, andsaid i-th differential coded moving picture sequence signal is in theform of a hierarchical structure including one or more sequence layerseach having a plurality of screens sharing common information, one ormore picture layers each having a plurality of slices sharing commoninformation with respect to one of said screens, one or more slicelayers each having a plurality of macroblocks with respect to one ofsaid slices, one or more macroblock layers each having a plurality ofblocks with respect to one of said macroblocks, and one or more blocklayers each having block information with respect to one of said blocks,and said step (B1) is the step of inputting said 1st second coded movingpicture sequence signal and said 1st differential coded moving picturesequence signal to reconstruct said first coded moving picture sequencesignal, whereby said step (Bi) includes the steps of: (Bi-1) receiving abase coded moving picture sequence signal, said base coded movingpicture sequence signal being any one of said i-th second coded movingpicture sequence signal, said (i−1)-th second coded moving picturesequence signal, and said i-th differential coded moving picturesequence signal; (Bi-2) storing said base coded moving picture sequencesignal received in said step (Bi-1); (Bi-3) determining a request signalfor a requested coded moving picture sequence signal on the basis ofsaid base coded moving picture sequence signal stored in said step(Bi-2); (Bi-4) transmitting said request signal for said requested codedmoving picture sequence signal determined in said step (Bi-3); (Bi-5)receiving said requested coded moving picture sequence signal; (Bi-6)extracting said base coded moving picture sequence signal from amongcoded moving picture sequence signals stored in said step (Bi-2); (Bi-7)merging said base coded moving picture sequence signal extracted in saidstep (Bi-6) with said requested coded moving picture sequence signalreceived in said step (Bi-5) to reconstruct said (i−1)-th second codedmoving picture sequence signal on the basis of said i-th secondcoefficient information obtained from said series of i-th second pictureinformation of said i-th second coded moving picture sequence signal,and said i-th differential coefficient information obtained from saidi-th differential coded signal; and (Bi-8) inputting said reconstructedi-th second coded moving picture sequence signal from said step (Bi-7)to be outputted therethrough, said step (B1) includes the steps of:(B1-1) receiving a base coded moving picture sequence signal, said basecoded moving picture sequence signal being any one of said first codedmoving picture sequence signal, said 1st second coded moving picturesequence signal, and said 1st differential coded moving picture sequencesignal; (B1-2) storing said base coded moving picture sequence signalreceived in said step (B1-1); (B1-3) determining a request signal for arequested coded moving picture sequence signal on the basis of said basecoded moving picture sequence signal stored in said step (B1-2); (B1-4)transmitting said request signal for said requested coded moving picturesequence signal determined in said step (B1-3); (B1-5) receiving saidrequested coded moving picture sequence signal; (B1-6) extracting saidbase coded moving picture sequence signal from among coded movingpicture sequence signals stored in said step (B1-2); (B1-7) merging saidbase coded moving picture sequence signal extracted in said step (B1-6)with said requested coded moving picture sequence signal received insaid step (B1-5) to reconstruct said first coded moving picture sequencesignal on the basis of said 1st second coefficient information obtainedfrom said series of 1st second picture information of said 1st secondcoded moving picture sequence signal, and said 1st differentialcoefficient information obtained from said 1st differential codedsignal; and (B1-8) inputting said reconstructed first coded movingpicture sequence signal from said step (B1-7) to be outputtedtherethrough.
 59. A multi-output coded signal separating method as setforth in claim 57, in said step (Ai), said step (Ai-4) has the step ofstoring said (i−1)-th differential coded moving picture sequence signalgenerated in said step (Ai-3), said step (Ai-5) has the step oftransmitting said (i−1)-th second coded moving picture sequence signalgenerated in said step (Ai-2), said step (Ai-6) has the step ofreceiving said request signal indicative of a requested (i−1)-thdifferential coded moving picture sequence signal to be transmitted,said request signal indicative of said requested (i−1)-th differentialcoded moving picture sequence signal being determined on the basis ofsaid (i−1)-th second coded moving picture sequence signal, said step(Ai-7) has the step of extracting said requested (i−1)-th differentialcoded moving picture sequence signal from among coded moving picturesequence signals stored in said step (Ai-4) in response to said requestsignal, and said step (Ai-8) has the step of transmitting said requested(i−1)-th differential coded moving picture sequence signal extracted insaid step (Ai-7) whereby said step (A) has the step of inputting a firstcoded moving picture sequence signal to separate into a plurality ofsecond coded moving picture sequence signals and a plurality ofdifferential coded moving picture sequence signals.
 60. A multi-inputcoded signal merging method as set forth in claim 58, in said step (Bi),said step (Bi-1) has the step of receiving said i-th second coded movingpicture sequence signal, said step (Bi-2) has the step of storing saidi-th second coded moving picture sequence signal received in said step(Bi-1), said step (Bi-3) has the step of determining a request signalfor a requested differential coded moving picture sequence signal on thebasis of said i-th second coded moving picture sequence signal stored insaid step (Bi-2), said step (Bi-4) has the step of transmitting saidrequest signal for said requested differential coded moving picturesequence signal determined in said step (Bi-3), said step (Bi-5) has thestep of receiving said requested differential coded moving picturesequence signal, said step (Bi-6) has the step of extracting said i-thsecond coded moving picture sequence signal from among coded movingpicture sequence signals stored in said step (Bi-2), and said step(Bi-7) has the step of merging said i-th second coded moving picturesequence signal extracted in said step (Bi-6) with said requesteddifferential coded moving picture sequence signal received in said step(Bi-5) to reconstruct said (i−1)-th second coded moving picture sequencesignal wherein said 0-th second coded moving picture sequence signal issaid first coded moving picture sequence signal.
 61. A coded signalseparating and merging method comprising the steps of: (A) inputting afirst coded moving picture sequence signal to separate into a pluralityof second coded moving picture sequence signals and a plurality ofdifferential coded moving picture sequence signals; and (B) inputting aplurality of second coded moving picture sequence signals and aplurality of differential coded moving picture sequence signals toreconstruct said first coded moving picture sequence signal, said step(A) including a plurality of steps (A1 to Am) including a step (A1) upto a step (Am) wherein m is an integer not less than two; said step (B)including a plurality of steps (B1 to Bn) including a step (B1) up to astep (Bn) wherein n is an integer not less than two and equal to or lessthan said m, said step (Ai) including the steps of: (Ai-1) inputting an(i−1)-th second coded moving picture sequence signal therethrough fromsaid step (A(i−1)), said (i−1)-th second coded moving picture sequencesignal generated as a result of encoding original moving picturesequence signal and consisting of a series of (i−1)-th second pictureinformation having (i−1)-th second coefficient information, said(i−1)-th second coefficient information including a matrix of (i−1)-thsecond coefficients wherein i is an integer equal to or less than m, andO-th second coded moving picture sequence signal is said first codedmoving picture sequence signal; (Ai-2) converting said (i−1)-th secondcoded moving picture sequence signal inputted through said step (Ai-1)to generate an i-th second coded moving picture sequence signal, saidi-th second coded moving picture sequence signal consisting of a seriesof i-th second picture information having i-th second coefficientinformation, said i-th second coefficient information including a matrixof second coefficients, each of said (i−1)-th second coded movingpicture sequence signal, and said i-th second coded moving picturesequence signal is in the form of a hierarchical structure including oneor more sequence layers each having a plurality of screens sharingcommon information, one or more picture layers each having a pluralityof slices sharing common information with respect to one of saidscreens, one or more slice layers each having a plurality of macroblockswith respect to one of said slices, one or more macroblock layers eachhaving a plurality of blocks with respect to one of said macroblocks,and one or more block layers each having block information with respectto one of said blocks; (Ai-3) inputting said (i−1)-th second codedmoving picture sequence signal and said i-th second coded moving picturesequence signal from said step (Ai-2) to generate an l-th differentialcoded moving picture sequence signal on the basis of said (i−1)-thsecond coefficient information obtained from said series of (i−1)-thsecond picture information of said (i−1)-th second coded moving picturesequence signal, and said i-th second coefficient information obtainedfrom said series of said i-th second picture information of said i-thsecond coded moving picture sequence signal, said i-th differentialcoded moving picture sequence signal being a difference between said(i−1)-th second coded moving picture sequence signal and said i-thsecond coded moving picture sequence signal; (Ai-4) selectively storingsaid (i−1)-th second coded moving picture sequence signal, said i-thsecond coded moving picture sequence signal, and said i-th differentialcoded moving picture sequence signal; and (Ai-5) selectivelytransmitting said (i−1)-th second coded moving picture sequence signal,said i-th second coded moving picture sequence signal, and said i-thdifferential coded moving picture sequence signal to said step (Bi);said step (Bi) including the steps of: (Bi-1) receiving a base codedmoving picture sequence signal from said step (Ai) or said step(B(i+1)), said base coded moving picture sequence signal being any oneof said (i−1)-th second coded moving picture sequence signal, said i-thsecond coded moving picture sequence signal, and said i-th differentialcoded moving picture sequence signal; (Bi-2) storing said base codedmoving picture sequence signal received in said step (Bi-1); (Bi-3)determining a request signal for a requested coded moving picturesequence signal on the basis of said base coded moving picture sequencesignal stored in said step (Bi-2); and (Bi-4) transmitting said requestsignal for said requested coded moving picture sequence signaldetermined in said step (Bi-3) to said step (Ai); whereby said step (Ai)further includes the steps of: (Ai-6) receiving said request signaltransmitted in said step (Bi-4); (Ai-7) extracting said requested codedmoving picture sequence signal from among coded moving picture sequencesignals stored in said step (Ai-4) in response to said request signal;and (Ai-8) transmitting said requested coded moving picture sequencesignal extracted in said step (Ai-7) to said step (Bi); said step (Bi)includes the steps of: (Bi-5) receiving said requested coded movingpicture sequence signal transmitted in said step (Ai-8) from said step(Ai); (Bi-6) extracting said base coded moving picture sequence signalfrom among coded moving picture sequence signals stored in said step(Bi-2); (Bi-7) merging said base coded moving picture sequence signalextracted in said step (Bi-6) with said requested coded moving picturesequence signal received in said step (Bi-5) on the basis of said i-thsecond coefficient information obtained from said series of secondpicture information of said i-th second coded moving picture sequencesignal, and said i-th differential coefficient information obtained fromsaid i-th differential coded signal to reconstruct said (i−1)-th secondcoded moving picture sequence signal; and (Bi-8) inputting saidreconstructed (i−1)-th second coded moving picture sequence signal fromsaid step (Bi-7) to be outputted therethrough.
 62. A coded signalseparating and merging method as set forth in claim 61 in which saidstep (Ai-4) has the step of storing said i-th differential coded movingpicture sequence signal generated in said step (Ai-3), said step (Ai-5)has the step of transmitting said i-th second coded moving picturesequence signal generated in said step (Ai-2), said step (Bi-1) has thestep of receiving said i-th second coded moving picture sequence fromsaid step (B(i+1)), said step (Bi-2) has the step of storing said i-thsecond coded moving picture sequence signal received in said step(Bi-1), said step (Bi-3) has the step of determining a request signalfor a requested differential coded moving picture sequence signal on thebasis of said i-th second coded moving picture sequence signal stored insaid step (Bi-2), said step (Bi-4) has the step of transmitting saidrequest signal for said requested differential coded moving picturesequence signal determined in said step (Bi-3), said step (Ai-6) has thestep of receiving said request signal transmitted in said step (Bi-4),said step (Ai-7) has the step of extracting said requested differentialcoded moving picture sequence signal from among coded moving picturesequence signals stored in said step (Ai-4) in response to said requestsignal, said step (Ai-8) has the step of transmitting said requesteddifferential coded moving picture sequence signal extracted in said step(Ai-7) to said step (Bi), said step (Bi-5) has the step of receivingsaid requested differential coded moving picture sequence signaltransmitted in said step (Ai-8), said step (Bi-6) has the step ofextracting said i-th second coded moving picture sequence signal fromamong coded moving picture sequence signals stored in said step (Bi-2),and said step (Bi-7) has the step of merging said i-th second codedmoving picture sequence signal extracted in said step (Bi-6) with saidrequested differential coded moving picture sequence signal received insaid step (Bi-5) to reconstruct said first coded moving picture sequencesignal. 63-87. (canceled)
 88. A computer program product comprising acomputer usable storage medium having computer readable code embodiedtherein for inputting a first coded moving picture sequence signal toseparate into a plurality of second coded moving picture sequencesignals and a plurality of differential coded moving picture sequencesignals comprising a plurality of computer readable program codes (A1 toAm) including computer readable program code (A-1) up to computerreadable program codes (Am) wherein m is an integer not less than two;said computer readable program code (A-1) is computer readable programcode for inputting said first coded moving picture sequence signal toseparate into a 1st second coded moving picture sequence signal and a1st differential coded moving picture sequence signal, said 1stdifferential coded moving picture sequence signal being a differencebetween said first coded moving picture sequence signal and said 1stsecond coded moving picture sequence signal, and said computer readableprogram code (Ai) is computer readable program code for inputting an(i−1)-th second coded moving picture sequence signal to separate into ani-th second coded moving picture sequence signal and an i-thdifferential coded moving picture sequence signal, said i-thdifferential coded moving picture sequence signal being a differencebetween said (i−1)-th second coded moving picture sequence signal andsaid i-th second coded moving picture sequence signal wherein i is aninteger equal to or less than m, whereby said computer readable programcode (A-1) includes: (A1-1) computer readable program code for inputtingsaid first coded moving picture sequence signal therethrough, said firstcoded moving picture sequence signal generated as a result of encodingoriginal moving picture sequence signal and consisting of a series offirst picture information having first coefficient information, saidfirst coefficient information including a matrix of first coefficients;(A1-2) computer readable program code for converting said first codedmoving picture sequence signal inputted by said computer readableprogram code (A1-1) to generate a 1st second coded moving picturesequence signal, said 1st second coded moving picture sequence signalconsisting of a series of 1st second picture information having 1stsecond coefficient information, said 1st second coefficient informationincluding a matrix of 1st second coefficients, each of said first codedmoving picture sequence signal, and said 1st second coded moving picturesequence signal is in the form of a hierarchical structure including oneor more sequence layers each having a plurality of screens sharingcommon information, one or more picture layers each having a pluralityof slices sharing common information with respect to one of saidscreens, one or more slice layers each having a plurality of macroblockswith respect to one of said slices, one or more macroblock layers eachhaving a plurality of blocks with respect to one of said macroblocks,and one or more block layers each having block information with respectto one of said blocks; (A1-3) computer readable program code forinputting said first coded moving picture sequence signal and said 1stsecond coded moving picture sequence signal from said computer readableprogram code (A1-2) to generate a 1st differential coded moving picturesequence signal on the basis of said first coefficient informationobtained from said series of first picture information of said firstcoded moving picture sequence signal, and said 1st second coefficientinformation obtained from said series of said 1st second pictureinformation of said 1st second coded moving picture sequence signal,said 1st differential coded moving picture sequence signal being adifference between said first coded moving picture sequence signal andsaid 1st second coded moving picture sequence signal; (A1-4) computerreadable program code for selectively storing said first coded movingpicture sequence signal, said 1st second coded moving picture sequencesignal, and said 1st differential coded moving picture sequence signal;(A1-5) computer readable program code for selectively transmitting saidfirst coded moving picture sequence signal, said 1st second coded movingpicture sequence signal, and said 1st differential coded moving picturesequence signal; (A1-6) computer readable program code for receiving arequest signal indicative of a requested coded moving picture sequencesignal to be transmitted, said request signal indicative of saidrequested coded moving picture sequence signal being determined on thebasis of said first coded moving picture sequence signal, said 1stsecond coded moving picture sequence signal, or said 1st differentialcoded moving picture sequence signal; (A1-7) computer readable programcode for extracting said requested coded moving picture sequence signalfrom among coded moving picture sequence signals stored by said computerreadable program code (A1-4) in response to said request signal; and(A1-8) computer readable program code for transmitting said requestedcoded moving picture sequence signal extracted by said computer readableprogram code (A1-7), and said computer readable program code (Ai)includes: (Ai-1) computer readable program code for inputting said(i−1)-th second coded moving picture sequence signal therethrough fromsaid computer readable program code (A(i−1)), said (i−1)-th second codedmoving picture sequence signal generated as a result of encodingoriginal moving picture sequence signal and consisting of a series of(i−1)-th second picture information having (i−1)-th second coefficientinformation, said (i−1)-th second coefficient information including amatrix of (i−1)-th second coefficients; (Ai-2) computer readable programcode for converting said (i−1)-th second coded moving picture sequencesignal inputted through said computer readable program code (Ai-1) togenerate said i-th second coded moving picture sequence signal, saidi-th second coded moving picture sequence signal consisting of a seriesof i-th second picture information having i-th second coefficientinformation, said i-th second coefficient information including a matrixof i-th second coefficients, each of said (i−1)-th second coded movingpicture sequence signal, and said i-th second coded moving picturesequence signal is in the form of a hierarchical structure including oneor more sequence layers each having a plurality of screens sharingcommon information, one or more picture layers each having a pluralityof slices sharing common information with respect to one of saidscreens, one or more slice layers each having a plurality of macroblockswith respect to one of said slices, one or more macroblock layers eachhaving a plurality of blocks with respect to one of said macroblocks,and one or more block layers each having block information with respectto one of said blocks; (Ai-3) computer readable program code forinputting said (i−1)-th second coded moving picture sequence signal andsaid i-th second coded moving picture sequence signal from said computerreadable program code (Ai-2) to generate an i-th differential codedmoving picture sequence signal on the basis of said (i−1)-th secondcoefficient information obtained from said series of (i−1)-th secondpicture information of said (i−1)-th second coded moving picturesequence signal, and said i-th second coefficient information obtainedfrom said series of said i-th second picture information of said i-thsecond coded moving picture sequence signal, said i-th differentialcoded moving picture sequence signal being a difference between said(i−1)-th second coded moving picture sequence signal and said i-thsecond coded moving picture sequence signal; (Ai-4) computer readableprogram code for selectively storing said (i−1)-th second coded movingpicture sequence signal, said i-th second coded moving picture sequencesignal, and said i-th differential coded moving picture sequence signal;(Ai-5) computer readable program code for selectively transmitting said(i−1)-th second coded moving picture sequence signal, said i-th secondcoded moving picture sequence signal, and said i-th differential codedmoving picture sequence signal; (Ai-6) computer readable program codefor receiving a request signal indicative of a requested coded movingpicture sequence signal to be transmitted, said request signalindicative of said requested coded moving picture sequence signal beingdetermined on the basis of said (i−1)-th second coded moving picturesequence signal, said i-th second coded moving picture sequence signal,or said i-th differential coded moving picture sequence signal; (Ai-7)computer readable program code for extracting said requested codedmoving picture sequence signal from among coded moving picture sequencesignals stored by said computer readable program code (Ai-4) in responseto said request signal; and (Ai-8) computer readable program code fortransmitting said requested coded moving picture sequence signalextracted by said computer readable program code (Ai-7).
 89. A computerprogram product comprising a computer usable storage medium havingcomputer readable code embodied therein for inputting a plurality ofsecond coded moving picture sequence signals and a plurality ofdifferential coded moving picture sequence signals to reconstruct afirst coded moving picture sequence signal comprising a plurality ofcomputer readable program code (B1 to Bn) including computer readableprogram code (B-1) up to a computer readable program code (Bn) wherein nis an integer not less than two, said computer readable program code(Bi) has computer readable program code for inputting a i-th secondcoded moving picture sequence signal and a i-th differential codedmoving picture sequence signal to reconstruct an (i−1)-th second codedmoving picture sequence signal wherein i is an integer equal to or lessthan n, said i-th second coded moving picture sequence signal generatedas a result of transcoding said (i−1)-th second coded moving picturesequence signal and consisting of a series of i-th second pictureinformation having i-th second coefficient information, said i-th secondcoefficient information including a matrix of i-th second coefficients,said (i−1)-th second coded moving picture sequence signal generated as aresult of encoding original moving picture sequence signal andconsisting of a series of (i−1)-th second picture information having(i−1)-th second coefficient information, said (i−1)-th secondcoefficient information including a matrix of (i−1)-th secondcoefficients, said i-th differential coded moving picture sequencesignal being a difference between said i-th second coded moving picturesequence signal and said (i−1)-th second coded moving picture sequencesignal, said i-th differential coded moving picture sequence signalincluding i-th differential coefficient information between said i-thsecond coefficient information and said (i−1)-th second coefficientinformation, each of said i-th second coded moving picture sequencesignal, said (i−1)-th second coded moving picture sequence signal, andsaid i-th differential coded moving picture sequence signal is in theform of a hierarchical structure including one or more sequence layerseach having a plurality of screens sharing common information, one ormore picture layers each having a plurality of slices sharing commoninformation with respect to one of said screens, one or more slicelayers each having a plurality of macroblocks with respect to one ofsaid slices, one or more macroblock layers each having a plurality ofblocks with respect to one of said macroblocks, and one or more blocklayers each having block information with respect to one of said blocks,and said computer readable program code (B-1) is computer readableprogram code for inputting said 1st second coded moving picture sequencesignal and said 1st differential coded moving picture sequence signal toreconstruct said first coded moving picture sequence signal, wherebysaid computer readable program code (Bi) includes: (Bi-1) computerreadable program code for receiving a base coded moving picture sequencesignal, said base coded moving picture sequence signal being any one ofsaid i-th second coded moving picture sequence signal, said (i−1)-thsecond coded moving picture sequence signal, and said i-th differentialcoded moving picture sequence signal; (Bi-2) computer readable programcode for storing said base coded moving picture sequence signal receivedby said computer readable program code (Bi-1); (Bi-3) computer readableprogram code for determining a request signal for a requested codedmoving picture sequence signal on the basis of said base coded movingpicture sequence signal stored by said computer readable program code(Bi-2); (Bi-4) computer readable program code for transmitting saidrequest signal for said requested coded moving picture sequence signaldetermined by said computer readable program code (Bi-3); (Bi-5)computer readable program code for receiving said requested coded movingpicture sequence signal; (Bi-6) computer readable program code forextracting said base coded moving picture sequence signal from amongcoded moving picture sequence signals stored by said computer readableprogram code (Bi-2); (Bi-7) computer readable program code for mergingsaid base coded moving picture sequence signal extracted by saidcomputer readable program code (Bi-6) with said requested coded movingpicture sequence signal received by said computer readable program code(Bi-5) to reconstruct said (i−1)-th second coded moving picture sequencesignal on the basis of said i-th second coefficient information obtainedfrom said series of i-th second picture information of said i-th secondcoded moving picture sequence signal, and said i-th differentialcoefficient information obtained from said i-th differential codedsignal; and (Bi-8) computer readable program code for inputting saidreconstructed i-th second coded moving picture sequence signal from saidcomputer readable program code (Bi-7) to be outputted therethrough, saidcomputer readable program code (B-1) includes: (B1-1) computer readableprogram code for receiving a base coded moving picture sequence signal,said base coded moving picture sequence signal being any one of saidfirst coded moving picture sequence signal, said 1st second coded movingpicture sequence signal, and said 1st differential coded moving picturesequence signal; (B1-2) computer readable program code for storing saidbase coded moving picture sequence signal received by said computerreadable program code (B1-1); (B1-3) computer readable program code fordetermining a request signal for a requested coded moving picturesequence signal on the basis of said base coded moving picture sequencesignal stored by said computer readable program code (b-12); (B1-4)computer readable program code for transmitting said request signal forsaid requested coded moving picture sequence signal determined by saidcomputer readable program code (B1-3); (B1-5) computer readable programcode for receiving said requested coded moving picture sequence signal;(B1-6) computer readable program code for extracting said base codedmoving picture sequence signal from among coded moving picture sequencesignals stored by said computer readable program code (b-12); (B1-7)computer readable program code for merging said base coded movingpicture sequence signal extracted by said computer readable program code(B1-6) with said requested coded moving picture sequence signal receivedby said computer readable program code (B1-5) to reconstruct said firstcoded moving picture sequence signal on the basis of said 1st secondcoefficient information obtained from said series of 1st second pictureinformation of said 1st second coded moving picture sequence signal, andsaid 1st differential coefficient information obtained from said 1stdifferential coded signal; and (B1-8) computer readable program code forinputting said reconstructed first coded moving picture sequence signalfrom said computer readable program code (B1-7) to be outputtedtherethrough.
 90. A computer program product as set forth in claim 88,by said computer readable program code (Ai), said computer readableprogram code (Ai-4) has computer readable program code for storing said(i−1)-th differential coded moving picture sequence signal generated bysaid computer readable program code (Ai-3), said computer readableprogram code (Ai-5) has computer readable program code for transmittingsaid (i−1)-th second coded moving picture sequence signal generated bysaid computer readable program code (Ai-2), said computer readableprogram code (Ai-6) has computer readable program code for receivingsaid request signal indicative of a requested (i−1)-th differentialcoded moving picture sequence signal to be transmitted, said requestsignal indicative of said requested (i−1)-th differential coded movingpicture sequence signal being determined on the basis of said (i−1)-thsecond coded moving picture sequence signal, said computer readableprogram code (Ai-7) has computer readable program code for extractingsaid requested (i−1)-th differential coded moving picture sequencesignal from among coded moving picture sequence signals stored by saidcomputer readable program code (Ai-4) in response to said requestsignal, and said computer readable program code (Ai-8) has computerreadable program code for transmitting said requested (i−1)-thdifferential coded moving picture sequence signal extracted by saidcomputer readable program code (Ai-7) whereby said computer readableprogram code (A) has computer readable program code for inputting afirst coded moving picture sequence signal to separate into a pluralityof second coded moving picture sequence signals and a plurality ofdifferential coded moving picture sequence signals.
 91. A computerprogram product as set forth in claim 89, by said computer readableprogram code (Bi), said computer readable program code (Bi-1) hascomputer readable program code for receiving said i-th second codedmoving picture sequence signal, said computer readable program code(Bi-2) has computer readable program code for storing said i-th secondcoded moving picture sequence signal received by said computer readableprogram code (Bi-1), said computer readable program code (Bi-3) hascomputer readable program code for determining a request signal for arequested differential coded moving picture sequence signal on the basisof said i-th second coded moving picture sequence signal stored by saidcomputer readable program code (Bi-2), said computer readable programcode (Bi-4) has computer readable program code for transmitting saidrequest signal for said requested differential coded moving picturesequence signal determined by said computer readable program code(Bi-3), said computer readable program code (Bi-5) has computer readableprogram code for receiving said requested differential coded movingpicture sequence signal, said computer readable program code (Bi-6) hascomputer readable program code for extracting said i-th second codedmoving picture sequence signal from among coded moving picture sequencesignals stored by said computer readable program code (Bi-2), and saidcomputer readable program code (Bi-7) has computer readable program codefor merging said i-th second coded moving picture sequence signalextracted by said computer readable program code (Bi-6) with saidrequested differential coded moving picture sequence signal received bysaid computer readable program code (Bi-5) to reconstruct said (i−1)-thsecond coded moving picture sequence signal wherein said 0-th secondcoded moving picture sequence signal is said first coded moving picturesequence signal.
 92. A computer program product comprising a computerusable storage medium having computer readable code embodied therein forseparating and merging coded signal comprising: (A) computer readableprogram code for inputting a first coded moving picture sequence signalto separate into a plurality of second coded moving picture sequencesignals and a plurality of differential coded moving picture sequencesignals; and (B) computer readable program code for inputting aplurality of second coded moving picture sequence signals and aplurality of differential coded moving picture sequence signals toreconstruct said first coded moving picture sequence signal, saidcomputer readable program code (A) including a plurality of computerreadable program codes (A1 to Am) including computer readable programcode (A-1) up to computer readable program codes (Am) wherein m is aninteger not less than two; said computer readable program code (b)including a plurality of computer readable program code (B1 to Bn)including computer readable program code (B-1) up to a computer readableprogram code (Bn) wherein n is an integer not less than two and equal toor less than said m, said computer readable program code (Ai) including:(Ai-1) computer readable program code for inputting an (i−1)-th secondcoded moving picture sequence signal therethrough from said computerreadable program code (A(i−1)), said (i−1)-th second coded movingpicture sequence signal generated as a result of encoding originalmoving picture sequence signal and consisting of a series of (i−1)-thsecond picture information having (i−1)-th second coefficientinformation, said (i−1)-th second coefficient information including amatrix of (i−1)-th second coefficients wherein i is an integer equal toor less than m, and 0-th second coded moving picture sequence signal issaid first coded moving picture sequence signal; (Ai-2) computerreadable program code for converting said (i−1)-th second coded movingpicture sequence signal inputted through said computer readable programcode (Ai−1) to generate an i-th second coded moving picture sequencesignal, said i-th second coded moving picture sequence signal consistingof a series of i-th second picture information having i-th secondcoefficient information, said i-th second coefficient informationincluding a matrix of second coefficients, each of said (i−1)-th secondcoded moving picture sequence signal, and said i-th second coded movingpicture sequence signal is in the form of a hierarchical structureincluding one or more sequence layers each having a plurality of screenssharing common information, one or more picture layers each having aplurality of slices sharing common information with respect to one ofsaid screens, one or more slice layers each having a plurality ofmacroblocks with respect to one of said slices, one or more macroblocklayers each having a plurality of blocks with respect to one of saidmacroblocks, and one or more block layers each having block informationwith respect to one of said blocks; (Ai-3) computer readable programcode for inputting said (i−1)-th second coded moving picture sequencesignal and said i-th second coded moving picture sequence signal fromsaid computer readable program code (Ai-2) to generate an i-thdifferential coded moving picture sequence signal on the basis of said(i−1)-th second coefficient information obtained from said series of(i−1)-th second picture information of said (i−1)-th second coded movingpicture sequence signal, and said i-th second coefficient informationobtained from said series of said i-th second picture information ofsaid i-th second coded moving picture sequence signal, said i-thdifferential coded moving picture sequence signal being a differencebetween said (i−1)-th second coded moving picture sequence signal andsaid i-th second coded moving picture sequence signal; (Ai-4) computerreadable program code for selectively storing said (i−1)-th second codedmoving picture sequence signal, said i-th second coded moving picturesequence signal, and said i-th differential coded moving picturesequence signal; and (Ai-5) computer readable program code forselectively transmitting said (i−1)-th second coded moving picturesequence signal, said i-th second coded moving picture sequence signal,and said i-th differential coded moving picture sequence signal to saidcomputer readable program code (Bi); said computer readable program code(Bi) including: (Bi-1) computer readable program code for receiving abase coded moving picture sequence signal from said computer readableprogram code (Ai) or said computer readable program code (B(i+1)), saidbase coded moving picture sequence signal being any one of said (i−1)-thsecond coded moving picture sequence signal, said i-th second codedmoving picture sequence signal, and said i-th differential coded movingpicture sequence signal; (Bi-2) computer readable program code forstoring said base coded moving picture sequence signal received by saidcomputer readable program code (Bi-1); (Bi-3) computer readable programcode for determining a request signal for a requested coded movingpicture sequence signal on the basis of said base coded moving picturesequence signal stored by said computer readable program code (Bi-2);and (Bi-4) computer readable program code for transmitting said requestsignal for said requested coded moving picture sequence signaldetermined by said computer readable program code (Bi-3) to saidcomputer readable program code (Ai); whereby said computer readableprogram code (Ai) further includes: (Ai-6) computer readable programcode for receiving said request signal transmitted by said computerreadable program code (Bi-4); (Ai-7) computer readable program code forextracting said requested coded moving picture sequence signal fromamong coded moving picture sequence signals stored by said computerreadable program code (Ai-4) in response to said request signal; and(Ai-8) computer readable program code for transmitting said requestedcoded moving picture sequence signal extracted by said computer readableprogram code (Ai-7) to said computer readable program code (Bi); saidcomputer readable program code (Bi) includes: (Bi-5) computer readableprogram code for receiving said requested coded moving picture sequencesignal transmitted by said computer readable program code (Ai-8) fromsaid computer readable program code (Ai); (Bi-6) computer readableprogram code for extracting said base coded moving picture sequencesignal from among coded moving picture sequence signals stored by saidcomputer readable program code (Bi-2); (Bi-7) computer readable programcode for merging said base coded moving picture sequence signalextracted by said computer readable program code (Bi-6) with saidrequested coded moving picture sequence signal received by said computerreadable program code (Bi-5) on the basis of said i-th secondcoefficient information obtained from said series of second pictureinformation of said i-th second coded moving picture sequence signal,and said i-th differential coefficient information obtained from saidi-th differential coded signal to reconstruct said (i−1)-th second codedmoving picture sequence signal; and (Bi-8) computer readable programcode for inputting said reconstructed (i−1)-th second coded movingpicture sequence signal from said computer readable program code (Bi-7)to be outputted therethrough.
 93. A computer program product as setforth in claim 92 in which said computer readable program code (Ai-4)has computer readable program code for storing said i-th differentialcoded moving picture sequence signal generated by said computer readableprogram code (Ai-3), said computer readable program code (Ai-5) hascomputer readable program code for transmitting said i-th second codedmoving picture sequence signal generated by said computer readableprogram code (Ai-2), said computer readable program code (Bi-1) hascomputer readable program code for receiving said i-th second codedmoving picture sequence signal from said computer readable program code(B(i+1)), said computer readable program code (Bi-2) has computerreadable program code for storing said i-th second coded moving picturesequence signal received by said computer readable program code (Bi-1),said computer readable program code (Bi-3) has computer readable programcode for determining a request signal for a requested differential codedmoving picture sequence signal on the basis of said i-th second codedmoving picture sequence signal stored by said computer readable programcode (Bi-2), said computer readable program code (Bi-4) has computerreadable program code for transmitting said request signal for saidrequested differential coded moving picture sequence signal determinedby said computer readable program code (Bi-3), said computer readableprogram code (Ai-6) has computer readable program code for receivingsaid request signal transmitted by said computer readable program code(Bi-4), said computer readable program code (Ai-7) has computer readableprogram code for extracting said requested differential coded movingpicture sequence signal from among coded moving picture sequence signalsstored by said computer readable program code (Ai-4) in response to saidrequest signal, said computer readable program code (Ai-8) has computerreadable program code for transmitting said requested differential codedmoving picture sequence signal extracted by said computer readableprogram code (Ai-7) to said computer readable program code (Bi), saidcomputer readable program code (Bi-5) has computer readable program codefor receiving said requested differential coded moving picture sequencesignal transmitted by said computer readable program code (Ai-8), saidcomputer readable program code (Bi-6) has computer readable program codefor extracting said i-th second coded moving picture sequence signalfrom among coded moving picture sequence signals stored by said computerreadable program code (Bi-2), and said computer readable program code(Bi-7) has computer readable program code for merging said i-th secondcoded moving picture sequence signal extracted by said computer readableprogram code (Bi-6) with said requested differential coded movingpicture sequence signal received by said computer readable program code(Bi-5) to reconstruct said first coded moving picture sequence signal.